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1.
  • Amin, Gul, et al. (författare)
  • ZnO nanorods-polymer hybrid white light emitting diode grown on a disposable paper substrate
  • 2011
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : John Wiley and Sons, Ltd. - 1862-6254 .- 1862-6270. ; 5:2, s. 71-73
  • Tidskriftsartikel (refereegranskat)abstract
    • We demonstrate intrinsic white light emission from hybrid light emitting diodes fabricated using an inorganic-organic hybrid junction grown at 50 C on a paper substrate. Cyclotene was first spin coated on the entire substrate to act as a surface barrier layer for water and other nutrient solutions. The active area of the fabricated light emitting diode (LED) consists of zinc oxide nanorods (ZnO NRs) and a poly(9,9-dioctylfluorene) (PFO) conducting polymer layer. The fabricated LED shows clear rectifying behavior and a broad band electroluminescence (EL) peak covering the whole visible spectrum range from 420 nm to 780 nm. The color rendering index (CRI) was calculated to be 94 and the correlated color temperature (CCT) of the LED was 3660 K. The low process temperature and procedure in this work enables the use of paper substrate for the fabrication of low cost ZnO-polymer white LEDs for applications requiring flexible/disposable electronic devices.
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2.
  • Balatsky, Alexander V., et al. (författare)
  • Functional Dirac Materials : Status and Perspectives
  • 2018
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlagsgesellschaft. - 1862-6254 .- 1862-6270. ; 12:11
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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3.
  • Brown, D. R., et al. (författare)
  • Relating phase transition heat capacity to thermal conductivity and effusivity in Cu2Se
  • 2016
  • Ingår i: Physica Status Solidi - Rapid Research Letetrs. - : Wiley. - 1862-6254 .- 1862-6270. ; 10:8, s. 618-621
  • Tidskriftsartikel (refereegranskat)abstract
    • Accurate measurement of thermal conductivity is essential to determine the thermoelectric figure-of-merit, zT. Near the phase transition of Cu2Se at 410 K, the transport properties change rapidly with temperature, and there is a concurrent peak in measured heat capacity from differential scanning calorimetry (DSC). Interpreting the origin as a broad increase in heat capacity or as a transient resulted in a three-fold difference in the reported zT in two recent publications. To resolve this discrepancy, thermal effusivity was deduced from thermal conductivity and diffusivity measurements via the transient plane source (TPS) method and compared with that calculated from thermal diffusivity and the two interpretations of the DSC data for heat capacity. The comparison shows that the DSC measurement gave the heat capacity relevant for calculation of the thermal conductivity of Cu2Se. The thermal conductivity calculated this way follows the electronic contribution to thermal conductivity closely, and hence the main cause of the zT peak is concluded to be the enhanced Seebeck coefficient.
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4.
  • Budich, Jan Carl, et al. (författare)
  • From the adiabatic theorem of quantum mechanics to topological states of matter
  • 2013
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 7:1-2, s. 109-129
  • Forskningsöversikt (refereegranskat)abstract
    • Owing to the enormous interest the rapidly growing field of topological states of matter (TSM) has attracted in recent years, the main focus of this review is on the theoretical foundations of TSM. Starting from the adiabatic theorem of quantum mechanics which we present from a geometrical perspective, the concept of TSM is introduced to distinguish gapped many body ground states that have representatives within the class of non-interacting systems and mean field superconductors, respectively, regarding their global geometrical features. These classifying features are topological invariants defined in terms of the adiabatic curvature of these bulk insulating systems. We review the general classification of TSM in all symmetry classes in the framework of K-Theory. Furthermore, we outline how interactions and disorder can be included into the theoretical framework of TSM by reformulating the relevant topological invariants in terms of the single particle Green's function and by introducing twisted boundary conditions, respectively. We finally integrate the field of TSM into a broader context by distinguishing TSM from the concept of topological order which has been introduced to study fractional quantum Hall systems.
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5.
  • Chey, Chan Oeurn, et al. (författare)
  • Fast piezoresistive sensor and UV photodetector based on Mn-doped ZnO nanorods
  • 2015
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : John Wiley & Sons. - 1862-6254 .- 1862-6270. ; 9:1, s. 87-91
  • Tidskriftsartikel (refereegranskat)abstract
    • A low cost hydrothermal synthesis method to synthesize Mn-doped ZnO nanorods (NRs) with controllable morphology and structure has been developed. Ammonia is used to tailor the ammonium hydroxide concentration, which provides a source of OH– for hydrolysis and precipitation during the growth instead of HMT. The morphological, chemical composition, structural, and electronic structure studies of the Mn-doped ZnO NRs show that the Mn-doped ZnO NRs have a hexagonal wurtzite ZnO structure along the c-axis and the Mn ions replace the Zn sites in the ZnO NRs matrix without any secondary phase of metallic manganese element and manganese oxides observed. The fabricated PEDOT:PSS/Zn0.85Mn0.15O Schottky diode based piezoresistive sensor and UV photodetector shows that the piezoresistive sensor has pressure sensitivity of 0.00617 kPa–1 for the pressure range from 1 kPa to 20 kP and 0.000180 kPa–1for the pressure range from 20 kPa to 320 kPa with relatively fast response time of 0.03 s and the UV photodetector has both relatively high responsivity and fast response time of 0.065 A/W and 2.75 s, respectively. The fabricated Schottky diode can be utilized as a very useful human-friendly interactive electronic device for mass/force sensor or UV photodetector in everyday living life. This developed device is very promising for small-size, low-cost and easy-to-customize application-specific requirements. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)
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6.
  • Cubarovs, Mihails, et al. (författare)
  • Epitaxial CVD growthof sp2-hybridized boron nitrideusing aluminum nitride as buffer layer
  • 2011
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlagsgesellschaft. - 1862-6254 .- 1862-6270. ; 5:10-11, s. 397-399
  • Tidskriftsartikel (refereegranskat)abstract
    • Epitaxial growth of sp2-hybridized boron nitride (BN) using chemical vapour deposition, with ammonia and triethyl boron as precursors, is enabled on sapphire by introducing an aluminium nitride (AlN) buffer layer. This buffer layer is formed by initial nitridation of the substrate. Epitaxial growth is verified by X-ray diffraction measurements in Bragg–Brentano configuration, pole figure measurements and transmission electron microscopy. The in-plane stretching vibration of sp2-hybridized BN is observed at 1366 cm–1 from Raman spectroscopy. Time-of-flight elastic recoil detection analysis confirms almost perfect stoichiometric BN with low concentration of carbon, oxygen and hydrogen contaminations.
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7.
  • Eklund, Per, et al. (författare)
  • Epitaxial TiC/SiC multilayers
  • 2007
  • Ingår i: Physica status solidi (RRL): rapid research letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 1:3, s. 113-115
  • Tidskriftsartikel (refereegranskat)abstract
    • Epitaxial TiC/SiC multilayers were grown by magnetron sputtering at a substrate temperature of 550 °C, where SiC is normally amorphous. The epitaxial TiC template induced growth of cubic SiC up to a thickness of ~2 nm. Thicker SiC layers result in a direct transition to growth of the metastable amorphous SiC followed by renucleation of nanocrystalline TiC layers
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8.
  • Ekström, Erik, 1989-, et al. (författare)
  • Epitaxial Growth of CaMnO3-y Films on LaAlO3 (112 over bar 0) by Pulsed Direct Current Reactive Magnetron Sputtering
  • 2022
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-V C H Verlag GMBH. - 1862-6254 .- 1862-6270. ; 16:4
  • Tidskriftsartikel (refereegranskat)abstract
    • CaMnO3 is a perovskite with attractive magnetic and thermoelectric properties. CaMnO3 films are usually grown by pulsed laser deposition or radio frequency magnetron sputtering from ceramic targets. Herein, epitaxial growth of CaMnO3-y (002) films on a (112 over bar 0)-oriented LaAlO3 substrate using pulsed direct current reactive magnetron sputtering is demonstrated, which is more suitable for industrial scale depositions. The CaMnO3-y shows growth with a small in-plane tilt of <approximate to 0.2 degrees toward the (200) plane of CaMnO3-y and the (1 over bar 104) with respect to the LaAlO3 (112 over bar 0) substrate. X-ray photoelectron spectroscopy of the electronic core levels shows an oxygen deficiency described by CaMnO2.58 that yields a lower Seebeck coefficient and a higher electrical resistivity when compared to stoichiometric CaMnO3. The LaAlO3 (112 over bar 0) substrate promotes tensile-strained growth of single crystals. Scanning transmission electron microscopy and electron energy loss spectroscopy reveal antiphase boundaries composed of Ca on Mn sites along and , forming stacking faults.
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9.
  • Emminger, Carola, et al. (författare)
  • Coherent acoustic phonon oscillations and transient critical point parameters of Ge from femtosecond pump‐probe ellipsometry
  • 2022
  • Ingår i: Physica Status Solidi - Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 16:7
  • Tidskriftsartikel (refereegranskat)abstract
    • The complex pseudodielectric function of Ge and Si from femtosecond pump-probe spectroscopic ellipsometry with 267, 400, and 800 nm pump-pulse wavelengths is analyzed by fitting analytical lineshapes to the second derivatives of the pseudodielectric function with respect to energy. This yields the critical point parameters (threshold energy, lifetime broadening, amplitude, and excitonic phase angle) of E1 and E1+Δ1 in Ge and E1 in Si as functions of delay time. Coherent longitudinal acoustic phonon oscillations with a period of about 11 ps are observed in the transient critical point parameters of Ge. From the amplitude of these oscillations, the laser-induced strain is found to be on the order of 0.1% for Ge measured with the 800 nm pump pulse, which is in reasonable agreement with the strain calculated from theory.
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10.
  • Fernando, Gayanath W., et al. (författare)
  • Correlation-Driven Magnetic Frustration and Insulating Behavior of TiF 3
  • 2024
  • Ingår i: Physica Status Solidi - Rapid Research Letetrs. - 1862-6254 .- 1862-6270. ; 18:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The halide perovskite TiF3, renowned for its intricate interplay between structure, electronic correlations, magnetism, and thermal expansion, is investigated. Despite its simple structure, understanding its low-temperature magnetic behavior has been a challenge. Previous theories propose antiferromagnetic ordering. In contrast, experimental signatures for an ordered magnetic state are absent down to 10 K. The current study has successfully reevaluated the theoretical modeling of TiF3, unveiling the significance of strong electronic correlations as the key driver for its insulating behavior and magnetic frustration. In addition, frequency-dependent optical reflectivity measurements exhibit clear signs of an insulating state. The analysis of the calculated magnetic data gives an antiferromagnetic exchange coupling with a net Weiss temperature of order 25 K as well as a magnetic response consistent with a S = 1/2 local moment per Ti3+. Yet, the system shows no susceptibility peak at this temperature scale and appears free of long-range antiferromagnetic order down to 1 K. Extending ab initio modeling of the material to larger unit cells shows a tendency for relaxing into a noncollinear magnetic ordering, with a shallow energy landscape between several magnetic ground states, promoting the status of this simple, nearly cubic perovskite structured material as a candidate spin liquid.
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11.
  • Geilhufe, R. Matthias, et al. (författare)
  • Chemical-Strain Induced Tilted Dirac Nodes in (BEDT-TTF)(2)X-3 (X = I, Cl, Br, F) Based Charge-Transfer Salts
  • 2018
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 12:11
  • Tidskriftsartikel (refereegranskat)abstract
    • The identification of novel multifunctional Dirac materials has been an ongoing effort. In this connection quasi 2-dimensional (BEDT-TTF)-based charge transfer salts are widely discussed. Here, we report about the electronic structure of alpha-(BEDT-TTF)(2)I-3 and kappa-(BEDT-TTF)(2)I-3 under a hypothetical substitution of iodine with the halogens bromine, chlorine, and fluorine. The decreasing size of the anion layer corresponds to applying chemical strain which increases tremendously in the case of (BEDT-TTF)(2)F-3. We perform structural optimization and electronic structure calculations in the framework of density functional theory, incorporating, first, the recently developed strongly constrained and appropriately normed semilocal density functional SCAN, and, second, van der Waals corrections to the PBE exchange correlation functional by means of the dDsC dispersion correction method. In the case of alpha-(BEDT-TTF)(2)F-3, the formation of over-tilted Dirac-type-II nodes within the quasi two-dimensional Brillouin zone can be found. For kappa-(BEDT-TTF)(2)F-3, the recently reported topological transition within the electronic band structure cannot be revealed.
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12.
  • Geilhufe, R. Matthias, et al. (författare)
  • Materials Informatics for Dark Matter Detection
  • 2018
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 12:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Dark Matter particles are commonly assumed to be weakly interacting massive particles (WIMPs) with a mass in the GeV to TeV range. However, recent interest has shifted toward lighter WIMPs, which are more difficult to probe experimentally. A detection of sub-GeV WIMPs will require the use of small gap materials in sensors. Using recent estimates of the WIMP mass, we identify the relevant target space toward small gap materials (100 to 10 meV). Dirac Materials, a class of small- or zero-gap materials, emerge as natural candidates for sensors for Dark Matter detection. We propose the use of informatics tools to rapidly assay materials band structures to search for small gap semiconductors and semimetals, rather than focusing on a few preselected compounds. As a specific example of the proposed strategy, we use the organic materials database () to identify organic candidates for sensors: the narrow band gap semiconductors BNQ-TTF and DEBTTT with gaps of 40 and 38 meV, and the Dirac-line semimetal (BEDT-TTF)center dot Br which exhibits a tiny gap of approximate to 50 meV when spin-orbit coupling is included. We outline a novel and powerful approach to search for dark matter detection sensor materials by means of a rapid assay of materials using informatics tools.
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13.
  • Jayathilaka, K. M. D. C., et al. (författare)
  • Surface treatment of electrodeposited n-type Cu2O thin films for applications in Cu2O based devices
  • 2014
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:6, s. 592-595
  • Tidskriftsartikel (refereegranskat)abstract
    • In this Letter, we report the effects of ammonium sulfide [(NH4)(2)S] surface treatment on electrical and optical characteristics of the electrodeposited n-type Cu2O thin films on Ti substrates. Films characterized structurally and morphologically before and after the surface treatment were compared using conductivity, spectral photoresponse and current-voltage (I-V) measurements. The ammonium sulfide surface treatment time showed an impact on optical and electrical characteristics of the films. Treated Cu2O films exhibited enhanced conductivity giving rise to a 50-fold increase in the photocurrent and improved I-V characteristics. It was found that the sulfur passivation resulted in a nearly ohmic behaviour for Au or Ni contacts made with n-type Cu2O whereas Ag or Cu contacts showed nearly Schottky behaviour. The results showed that ammonium sulfide treatments were very effective to passivate defects and improve the optical and electrical properties of polycrystalline n-type Cu2O thin films that may provide a solid platform for Cu2O based devices of enhanced quality. [GRAPHICS] .  
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14.
  • Joel, Jonathan, et al. (författare)
  • On the assessment of CIGS surface passivation by photoluminescence
  • 2015
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 9:5, s. 288-292
  • Tidskriftsartikel (refereegranskat)abstract
    • An optimized test structure to study rear surface passivation in Cu(In,Ga)Se-2 (CIGS) solar cells by means of photoluminescence (PL) is developed and tested. The structure - illustrated in the abstract figure - is examined from the rear side. To enable such rear PL assessment, a semi-transparent ultrathin Mo layer has been developed and integrated in place of the normal rear contact. The main advantages of this approach are (i) a simplified representation of a rear surface passivated CIGS solar cell is possible, (ii) it is possible to assess PL responses originating close to the probed rear surface, and (iii) a stable PL response as a function of air exposure time is obtained. In this work, PL measurements of such structures with and without rear surface passivation layers have been compared, and the measured improvement in PL intensity for the passivated structures is associated with enhanced CIGS rear interface properties. [GRAPHICS] Transmission electron microscope (TEM) bright field cross-section image of the rear illuminated test structure fabricated for PL characterization.
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15.
  • Kakanakova-Georgieva, Anelia, 1970-, et al. (författare)
  • Mg-doped Al0.85Ga0.15N layers grown by hot-wall MOCVD with low resistivity at room temperature
  • 2010
  • Ingår i: PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS. - : John Wiley and Sons, Ltd. - 1862-6254 .- 1862-6270. ; 4:11, s. 311-313
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on the hot-wall MOCVD growth of Mg-doped AlxGa1-xN layers with an Al content as high as x similar to 0.85. After subjecting the layers to post-growth in-situ annealing in nitrogen in the growth reactor, a room temperature resistivity of 7 k Omega cm was obtained indicating an enhanced p-type conductivity compared to published data for AlxGa1-xN layers with a lower Al content of x similar to 0.70 and a room temperature resistivity of about 10 k Omega cm. It is believed that the enhanced p-type conductivity is a result of reduced compensation by native defects through growth conditions enabled by the distinct hot-wall MOCVD system.
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16.
  • Kazi, Suraya, et al. (författare)
  • Correlating Photoconductivity and Optical Properties in Oxygen-Containing Yttrium Hydride Thin Films
  • 2023
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlagsgesellschaft. - 1862-6254 .- 1862-6270. ; 17:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Oxygen-containing yttrium hydride (YHO), primarily known for its photochromic properties, simultaneously shows a photoconductive response. Polycrystalline YHO thin films are deposited by reactive magnetron sputtering onto glass substrates and their optical and electrical properties are correlated under illumination with light. While photoconductivity is found in a broader range of compositions than photochromism, maximum photoconductive response is found for samples exhibiting photochromism. This photoconductive effect can be observed above a certain cutoff energy of light and a stronger response is triggered by shorter wavelengths. After the illumination is stopped, the slow recovery (few minutes) of the optical transmission and electrical transport suggests that the underlying process is not purely electronic. A memory effect is found depending on the previous exposure of samples to light which supports the hypothesis of local hydrogen diffusion during the photochromic reaction. An unprecedentedly fast bleaching speed is reported for samples stored in vacuum immediately after film deposition.
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17.
  • Khan, Azam, et al. (författare)
  • Harvesting piezoelectric potential from zinc oxide nanoflowers grown on textile fabric substrate
  • 2013
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlag. - 1862-6254 .- 1862-6270. ; 7:11, s. 980-984
  • Tidskriftsartikel (refereegranskat)abstract
    • ZnO nanoflowers were synthesized on conductive flexible textile fabric substrate by using the simple low-temperature aqueous chemical growth method and were used for piezoelectric energy harvesting source. Structural characterization of ZnO nanoflowers was carried out by using surface scanning electron microscopy and X-ray diffraction. The ZnO nanoflowers are uniformly grown over the entire sample. They are composed of needle-like nanorods, which have hexagonal wurtzite structure with good crystalline quality. The current-voltage characteristics showed good rectifying Schottky behaviour. Contact-mode atomic force microscopy was used for measuring the piezoelectric output potential. The maximum output potential was found to be more than 600 mV and the corresponding current also recorded was near approximate to 650 nA.
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18.
  • Knaup, Jan M., et al. (författare)
  • Focus on Functional Oxides Preface
  • 2014
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:6, s. 451-452
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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19.
  • Kotipalli, Ratan, et al. (författare)
  • Influence of Ga/(Ga plus In) grading on deep-defect states of Cu(In, Ga)Se-2 solar cells
  • 2015
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 9:3, s. 157-160
  • Tidskriftsartikel (refereegranskat)abstract
    • The benefits of gallium (Ga) grading on Cu(In, Ga) Se-2 (CIGS) solar cell performance are demonstrated by comparing with ungraded CIGS cells. Using drive-level capacitance profiling (DLCP) and admittance spectroscopy (AS) analyses, we show the influence of Ga grading on the spatial variation of deep defects, free-carrier densities in the CIGS absorber, and their impact on the cell's open-circuit voltage V-oc. The parameter most constraining the cell's Voc is found to be the deep-defect density close to the space charge region (SCR ). In ungraded devices, high deep-defect concentrations (4.2 x 1016 cm(-3)) were observed near the SCR, offering a source for Shockley Read-Hall recombination, reducing the cell's Voc. In graded devices, the deep-defect densities near the SCR decreased by one order of magnitude (2.5 x 1015 cm(-3)) for back surface graded devices, and almost two orders of magnitude (8.6 x 1014 cm(-3)) for double surface graded devices, enhancing the cell's Voc. In compositionally graded devices, the free-carrier density in the absorber's bulk decreased in tandem with the ratio of gallium to gallium plus indium ratio GGI = Ga/(Ga + In), increasing the activation energy, hindering the ionization of the defect states at room temperature and enhancing their role as recombination centers within the energy band.
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20.
  • Kullgren, Jolla, et al. (författare)
  • Reactive oxygen species in stoichiometric ceria : Bulk and low-index surfaces
  • 2014
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:6, s. 600-604
  • Tidskriftsartikel (refereegranskat)abstract
    • We have calculated the stabilities of some reactive oxygen species (ROS) in stoichiometric bulk ceria and at the low-index (111) and (110)-surfaces, both in vacuum and in the presence of additional O-2 molecules. We find that the formation of intrinsic ROS, here oxygen superoxides (O-2(-)) and peroxides (O-2(2-)), is always endothermic at vacuum conditions and that the superoxide formation always leads to a higher formation energy than the peroxide formation. In the presence of additional O-2 molecules, intrinsic peroxide formation becomes exothermic at the (110)-surface in conjunction with the formation of extrinsic superoxide ions from adsorbed O-2 molecules. This coexistence of intrinsic and extrinsic ROS species is anticipated to be stable at low temperatures, and can be important for understanding the ROS chemistry for nanoceria used in low-temperature applications. [GRAPHICS] Oxygen-assisted reduction of the ceria(110) surface. 
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21.
  • La Martina, Thomas, et al. (författare)
  • Dirac Nodes and Magnetic Order in M2X2 Transition-Metal Chalcogenides
  • 2018
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 12:11
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, we perform a computational analysis of the M2X2 transition-metal chalcogenides (TMCs). Using density functional theory with a spin-polarized generalized gradient approximation, we examine the magnetic and electronic properties for the antiferromagnetic and ferromagnetic states with M = Cr, Mn, and Fe and X = S and Se. After optimizing the geometric structure for stability, we examine the spin-polarized electronic structure, density of states, and Mulliken population. It is discovered that these materials are quasi-two-dimensional honeycomb lattices with metallic antiferromagnetic ground states. The structures consist of a distorted tetrahedral crystal-field symmetry that has a distinct magnetic moment. An analysis of the electronic structure shows the presence of nodal points that resemble Dirac nodes for all cases, which leads to the possibility of the realization of magnetic Dirac materials.
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22.
  • Li, Shunyi, et al. (författare)
  • Intrinsic energy band alignment of functional oxides
  • 2014
  • Ingår i: Physica Status Solidi - Rapid Research Letetrs. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:6, s. 571-576
  • Tidskriftsartikel (refereegranskat)abstract
    • The energy band alignment at interfaces between different materials is a key factor, which determines the function of electronic devices. While the energy band alignment of conventional semiconductors is quite well understood, systematic experimental studies on oxides are still missing. This work presents an extensive study on the intrinsic energy band alignment of a wide range of functional oxides using photoelectron spectroscopy with in-situ sample preparation. The studied materials have particular technological importance in diverse fields as solar cells, piezotronics, multiferroics, photoelectrochemistry and oxide electronics. Particular efforts have been made to verify the validity of transitivity, in order to confirm the intrinsic nature of the obtained band alignment and to understand the underlying principles. Valence band offsets up to 1.6 eV are observed. The large variation of valence band maximum energy can be explained by the different orbital contributions to the density of states in the valence band. The framework provided by this work enables the general understanding and prediction of energy band alignment at oxide interfaces, and furthermore the tailoring of energy level matching for charge transfer in functional oxides. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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23.
  • Li, Shanghua, et al. (författare)
  • Thermoelectric properties of CoSb3 with maize-like structure
  • 2007
  • Ingår i: Physica Status Solidi-Rapid Research Letter. - : Wiley. - 1862-6254 .- 1862-6270. ; 1:6, s. 259-261
  • Tidskriftsartikel (refereegranskat)abstract
    • Maize-like CoSb3 powders were obtained via the chemical alloying method. After the consolidation of the nanopowder using hot press, the CoSb3 compact shows a higher Seebeck coefficient and lower thermal conductivity. For the investigated CoSb3, a ZT of 0.15 at 673 K is shown. Though the achieved ZT does not reach the optimal value (0. 17 to 0. 18) for pure CoSb3, due to its lower electrical conductivity, the novel structure fabrication provides an interesting and promising approach to enhancing the thermoelectric performance.
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24.
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25.
  • Meshkian, Rahele, et al. (författare)
  • Theoretical stability, thin film synthesis and transport properties of the Mon+1GaCn MAX phase
  • 2015
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 9:3, s. 197-201
  • Tidskriftsartikel (refereegranskat)abstract
    • The phase stability of Mon +1GaCn has been investigated using ab-initio calculations. The results indicate stability for the Mo2GaC phase only, with a formation enthalpy of 0.4 meV per atom. Subsequent thin film synthesis of Mo2GaC was performed through magnetron sputtering from elemental targets onto Al2O3 [0001], 6H-SiC [0001] and MgO [111] substrates within the temperature range of 500 degrees C and 750 degrees C. High structural quality films were obtained for synthesis on MgO [111] substrates at 590 degrees C. Evaluation of transport properties showed a superconducting behavior with a critical temperature of approximately 7 K, reducing upon the application of an external magnetic field. The results point towards the first superconducting MAX phase in thin film form.
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26.
  • Mockuté, Aurelija, et al. (författare)
  • Synthesis and characterization of arc deposited magnetic (Cr,Mn)(2)AlC MAX phase films
  • 2014
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:5, s. 420-423
  • Tidskriftsartikel (refereegranskat)abstract
    • (Cr1-xMnx)(2)AlC MAX phase thin films were synthesized by cathodic arc deposition. Scanning transmission electron microscopy including local energy dispersive X-ray spectroscopy analysis of the as-deposited films reveals a Mn incorporation of as much as 10 at% in the structure, corresponding to x = 0.2. Magnetic properties were characterized with vibrating sample magnetometry, revealing a magnetic response up to at least room temperature. We thus verify previous theoretical predictions of an antiferromagnetic or ferromagnetic ground state for Cr2AlC upon alloying with Mn. ((c) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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27.
  • Mohseni, Seyed Majid, et al. (författare)
  • High frequency operation of a spin-torque oscillator at low field
  • 2011
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 5
  • Tidskriftsartikel (refereegranskat)abstract
    • We demonstrate a nano-contact based spin-torque oscillator (STO) combining a high operating frequency with low field operation. The STO is based on an orthogonal spin-valve architecture with an in-plane Co polarizer and an out-of-plane Co/Ni multilayer free layer. High frequency operation at low external fields is achieved by tailoring the Co/Ni layer properties to increase the strength (H(k)) of the perpendicular magnetic anisotropy, while simultaneously reducing the saturation magnetization (M(s)). Our approach emphasizes the importance of mu(0)(H(k)-M(s)) in determining the operating frequency in this system, and suggests that yet higher frequencies should be attainable through further optimization. [GRAPHICS]
  •  
28.
  • Moro, Marcos V., et al. (författare)
  • Photochromic Response of Encapsulated Oxygen-Containing Yttrium Hydride Thin Films
  • 2021
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : John Wiley & Sons. - 1862-6254 .- 1862-6270. ; 15:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Photochromic oxygen-containing yttrium-hydride thin films are synthesized by argon magnetron sputtering on microscope slides. Some of them are encapsulated with a thin, transparent, and nonphotochromic diffusion-barrier layer of either Al2O3 or Si3N4. Ion-beam-based methods prove that these protective diffusion barriers are stable and free from pinholes, with thicknesses of only a few tens of nanometers. Optical spectrophotometry reveals that the photochromic response and relaxation time for both protected and unprotected samples are almost identical. Ageing effects in the unprotected films lead to degradation of the photochromic performance (self-delamination), whereas the photochromic response for the encapsulated films is stable. The results show that the environment does not play a decisive role for the photochromic process and the encapsulation of oxygen-containing rare-earth hydride films with transparent and nonorganic thin diffusion-barrier layers provides long-time stability of the films, mandatory for applications as photochromic coatings on, e.g., smart windows.
  •  
29.
  • Moro, Marcos V., et al. (författare)
  • Photochromism in Isotopically Labeled Oxygen-Containing Yttrium-Hydride and Deuteride Thin-Film Systems
  • 2022
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : John Wiley & Sons. - 1862-6254 .- 1862-6270. ; 16:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Photochromic mono- and bilayered thin films of oxygen-containing isotope-labeled yttrium-hydride (i.e., protium and deuterium) are synthesized via reactive Ar sputtering. Selected samples are encapsulated with transparent diffusion barriers. Combining depth-resolved nondestructive ion beam-based techniques for composition and optical spectrophotometry, material mobility in the samples during illumination and over time is investigated. The results reveal that deuteride thin films exhibit a strong photochromic response equivalent to hydrogenated systems. No evidence of long-distance light-induced hydrogen mobility or thermal diffusion is found. The findings thus show that photochromism is not connected to long-distance material transport. The observations for encapsulated samples also exclude direct material exchange with the environment and any environmental influence on material mobility.
  •  
30.
  • Nguyen, Son Tien, et al. (författare)
  • Shallow donor in natural MoS2
  • 2015
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 9:12, s. 707-710
  • Tidskriftsartikel (refereegranskat)abstract
    • Using electron paramagnetic resonance and density functional theory calculations, we show that the shallow donor responsible for the n-type conductivity in natural MoS2 is rhenium (Re) with a typical concentration in the low 1017 cm–3 range and the g -values: g|| = 2.0274 and g⊥ = 2.2642. In bulk MoS2, the valley–orbit (VO) splitting and ionization energy of the Re shallow donor are determined to be ∼3 meV and ∼27 meV, respectively. Calculations show that the VO splitting of Re approaches the value in bulk if the number of MoS2 layers is larger than four and increases to 97.9 meV in a monolayer.
  •  
31.
  • Nishimoto, Yoshio, et al. (författare)
  • Theoretical investigation of molecular and electronic structure changes of the molecular magnet Mn-12 cluster upon super-reduction
  • 2014
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:6, s. 517-521
  • Tidskriftsartikel (refereegranskat)abstract
    • Density functional theory calculations on the neutral [Mn-12](0) molecular magnet and super-reduced [Mn-12](8-) cluster were employed to investigate the experimental geometrical changes observed during discharging in a molecular cluster battery. It was found that for relevant low-spin states the eight electrons added in [Mn-12](8-) are mainly added to the outer eight Mn atoms, causing elongation of the bonds between outer Mn and their surrounding O atoms, while the inner Mn-4 cluster is less affected by the reduction. [GRAPHICS] Schematic representation of the spin density of the neutral [Mn-12](0) cluster and its super-reduced state [Mn-12](8-), for which several possible spin states were found.
  •  
32.
  • Noël, Maxime, et al. (författare)
  • Probing structural integrity of single walled carbon nanotubes by dynamic and static compression
  • 2014
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:11, s. 935-938
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on a first study of single walled carbon nanotubes (SWCNTs) after application of dynamic (shock) compression. The experiments were conducted at 19 GPa and 36 GPa in a recovery assembly. For comparison, an experiment at a static pressure of 36 GPa was performed on the material from the same batch in a diamond anvil cell (DAC). After the high pressure treatment the samples were characterized by Raman spectroscopy and transmission electron microscopy (TEM). After exposure to 19 GPa of shock compression the CNT material exhibited substantial structural damage such as CNT wall disruption, opening of the tube along its axis (“unzipping”) and tube shortening (“cutting”). Dynamic compression to 36 GPa resulted in essentially complete CNT destruction whereas at least a fraction of the nanotubes was recovered after 36 GPa of static compression though severely damaged. The results of these shock wave experiments underline the prospect of using SWCNTs as reinforcing units in material
  •  
33.
  • Palisaitis, Justinas, et al. (författare)
  • Standard-free composition measurements of Alx In1–xN by low-loss electron energy loss spectroscopy
  • 2011
  • Ingår i: physica status solidi (RRL) – Rapid Research Letters. - : Wiley. - 1862-6270 .- 1862-6254. ; 5:2, s. 50-52
  • Tidskriftsartikel (refereegranskat)abstract
    • We demonstrate a standard-free method to retrieve compositional information in Alx In1–xN thin films by measuring the bulk plasmon energy (Ep), employing electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM). Two series of samples were grown by magnetron sputter epitaxy (MSE) and metal organic vapor phase epitaxy (MOVPE), which together cover the full com- positional range 0 ≤ x ≤ 1. Complementary compositional measurements were obtained using Rutherford backscattering spectroscopy (RBS) and the lattice parameters were obtained by X-ray diffraction (XRD). It is shown that Ep follows a linear relation with respect to composition and lattice parameter between the alloying elements from AlN to InN allowing for straightforward compositional analysis.
  •  
34.
  • Pedersen, Henrik, 1981-, et al. (författare)
  • Growth characteristics of chloride-based SiC epitaxial growth
  • 2008
  • Ingår i: Physica status solidi (RRL) - Rapid Research Letters. - : Wiley InterScience. - 1862-6270 .- 1862-6254. ; 2:6, s. 278-280
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study some aspects of the chloride-based CVD growth process have been investigated by using both the approach to add HCl to the standard precursors and by using the single molecule precursor methyltrichlorosilane (MTS). The efficiency of the process for different precursors, the growth rate stability and the effect that the C/Si and Cl/Si ratios have on the growth are studied. It is found that MTS is the most efficient precursor and that the growth becomes carbon limited at C/Si < 1.
  •  
35.
  • Pedersen, Henrik, 1981-, et al. (författare)
  • Very high crystalline quality of thick 4H-SiC epilayers grown from methyltrichlorosilane (MTS)
  • 2008
  • Ingår i: Physica status solidi (RRL) - Rapid Research Letters. - : Wiley InterScience. - 1862-6254 .- 1862-6270. ; 2:4, s. 188-190
  • Tidskriftsartikel (refereegranskat)abstract
    • 200 µm thick 4H-SiC epilayers have been grown by chloride-based chemical-vapor deposition using methyltrichlorosilane (MTS) as single precursor. The very high crystalline quality of the grown epilayer is demonstrated by high resolution X-Ray Diffraction rocking curve with a full-width-half-maximum value of only 9 arcsec. The high quality of the epilayer is further shown by low temperature photoluminescence showing strong free exciton and nitrogen bound exciton lines. The very high crystalline quality achieved for the thick epilayer grown in just two hours at 1600 °C suggests that MTS is a suitable precursor molecule for SiC bulk growth.
  •  
36.
  • Petruhins, Andrejs, et al. (författare)
  • Phase stability of Crn+1GaCn MAX phases from first principles and Cr2GaC thin-film synthesis using magnetron sputtering from elemental targets
  • 2013
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlag. - 1862-6254 .- 1862-6270. ; 7:11, s. 971-974
  • Tidskriftsartikel (refereegranskat)abstract
    • Ab-initio calculations have been used to investigate the phase stability and magnetic state of Crn+ 1GaCn MAX phase. Cr2GaC (n = 1) was predicted to be stable, with a ground state corresponding to an antiferromagnetic spin configuration. Thin-film synthesis by magnetron sputtering from elemental targets, including liquid Ga, shows the formation of Cr2GaC, previously only attained from bulk synthesis methods. The films were deposited at 650 degrees C on MgO(111) substrates. X-ray diffraction and high-resolution transmission electron microscopy show epitaxial growth of (000) MAX phase.
  •  
37.
  • Pournaghavi, Nezhat, et al. (författare)
  • Quantum Transport by Spin‐Polarized Edge States in Graphene Nanoribbons in the Quantum Spin Hall and Quantum Anomalous Hall Regimes
  • 2018
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-Blackwell. - 1862-6254 .- 1862-6270. ; 12:11, Special Issue
  • Tidskriftsartikel (refereegranskat)abstract
    • Using the non-equilibrium Green’s function method and the Keldysh formalism, we study the effects of spin–orbit interactions and time-reversal symmetry breaking exchange fields on non-equilibrium quantum transport in graphene armchair nanoribbons. We identify signatures of the quantum spin Hall (QSH) and the quantum anomalous Hall (QAH) phases in nonequilibrium edge transport by calculating the spin-resolved real space charge density and local currents at the nanoribbon edges. We find that the QSH phase, which is realized in a system with intrinsic spin–orbit coupling, is characterized by chiral counter-propagating local spin currents summing up to a net charge flow with opposite spin polarization at the edges. In the QAH phase, emerging in the presence of Rashba spin–orbit coupling and a ferromagnetic exchange field, two chiral edge channels with opposite spins propagate in the same direction at each edge, generating an unpolarized charge current and a quantized Hall conductance  . Increasing the intrinsic spin–orbit coupling causes a transition from the QAH to the QSH phase, evinced by characteristic changes in the non-equilibrium edge transport. In contrast, an antiferromagnetic exchange field can coexist with a QSH phase, but can never induce a QAH phase due to a symmetry that combines time-reversal and sublattice translational symmetry.
  •  
38.
  • Ramzan, Muhammad, et al. (författare)
  • Correlation effects in the electronic and structural properties of Cr2AlC
  • 2011
  • Ingår i: PHYS STATUS SOLIDI-RAPID RE L. - : Wiley. - 1862-6254 .- 1862-6270. ; 5:3, s. 122-124
  • Tidskriftsartikel (refereegranskat)abstract
    • In this Letter, we present the electronic and structural properties calculated by first principles GGA and GGA+U calculations of Cr2AlC, a member of the MAX phases family of compounds. While GGA fails to obtain a correct description, the GGA+U method successfully reproduces the experimental equilibrium volume and bulk modulus values of Cr2AlC, and predict it to be a ferromagnet. Therefore, correlation effects are crucial for the correct description of Cr2AlC, provided that a suitable value of U is chosen.
  •  
39.
  • Santoro, Gonzalo, et al. (författare)
  • Microfocus X-ray scattering and micro Raman spectroscopy: transcrystallinity in isotactic polypropylene
  • 2014
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlagsgesellschaft. - 1862-6254 .- 1862-6270. ; 8, s. 724-727
  • Tidskriftsartikel (refereegranskat)abstract
    • Microfocus X-ray scattering and micro Raman spectroscopy have been applied to study the β-transcrystalline morphology in isotactic polypropylene. The transformation from the α- to the β-form through the so-called bifurcation of growth mechanism has been investigated with high spatial resolution. We found that the mixed α–β region does not present spatial correlation along the shearing direction, implying that there is no cooperative crystallization from the different β-nucleation centres. In addition, a strong change in the lamellar orientation of the α-form thin layer that induces the growth of the β-crystallites has been observed for the first time. Finally, changes in the relative intensities of some selected Raman bands allowed the observation of the α–β transformation process at the molecular level.
  •  
40.
  • Sarakinos, Kostas, et al. (författare)
  • Ionized physical vapor deposited Al(2)O(3) films : Does subplantation favor formation of alpha-Al(2)O(3)?
  • 2010
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlag Berlin. - 1862-6254 .- 1862-6270. ; 4:7, s. 154-156
  • Tidskriftsartikel (refereegranskat)abstract
    • The broad energy distributions of the condensing particles typically encountered in ion assisted vapor deposition techniques are often a drawback when attempting to understand the effect of the energetic bombardment on the film properties. In the current study, a monoenergetic Al beam generated by a filtered cathodic arc discharge is employed for the deposition of alumina (Al(2)O(3)) films at well defined AI ion energies between 4 eV and 200 eV at a substrate temperature of 720 degrees C. Structural analysis shows that Al energies of 40 eV or larger favor the formation of the thermodynamically stable zeta-Al(2)O(3) phase at the expense of other metastable Al(2)O(3) polymorphs. The well defined ion energies are used as input for Monte-Carlo based simulations of the ion surface interactions. The results of these simulations reveal that the increase of the Al(+) ion energy leads to an increase in the fraction of ions subplanted into the growing film. These findings underline the previously not considered role of subsurface processes on the phase formation of ionized physical vapor deposited Al(2)O(3) films.
  •  
41.
  •  
42.
  • Soomro, Muhammad Yousuf, et al. (författare)
  • Piezoelectric power generation from zinc oxide nanowires grown on paper substrate
  • 2012
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlag Berlin. - 1862-6254 .- 1862-6270. ; 6:2, s. 80-82
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, we demonstrate piezoelectric power generation from zinc oxide (ZnO) nanowires grown on paper substrate. Vertically aligned ZnO nanowires are deflected by an atomic force microscopy (AFM) tip in contact mode which generates an output voltage of up to 7 mV. Furthermore, the effects of different parameters mainly influencing the magnitude of the output voltage are discussed. We expect that due to its simplicity, this approach represents an important step within the development of nanoscale power generators. It offers a promising alternative powering source for the next generation of nanodevices on disposable paper.
  •  
43.
  • Tress, Wolfgang, et al. (författare)
  • Photoconductivity as loss mechanism in organic solar cells
  • 2013
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlag. - 1862-6254 .- 1862-6270. ; 7:6, s. 401-405
  • Tidskriftsartikel (refereegranskat)abstract
    • We observe that the reverse current under illumination in solar cells containing C60 and ZnPc is dominated by a photoshunt. This shunt, not present in the dark, causes a linear current-voltage relation under illumination showing no saturation. Although observable in bulk heterojunctions, this effect is more pronounced in the presence of a pristine C60 layer. An internal quantum efficiency larger than unity under an applied negative voltage and in the spectral range where C60 absorbs identifies charges which are injected in addition to those photogenerated. The photoshunt is also present in the power-generating region and represents a loss mechanism limiting the fill factor in particular for flat heterojunction devices.
  •  
44.
  • Trinchero, Adriana, 1975, et al. (författare)
  • Metal-oxide sites for facile methane dissociation
  • 2014
  • Ingår i: Physica Status Solidi - Rapid Research Letetrs. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:6, s. 605-609
  • Tidskriftsartikel (refereegranskat)abstract
    • Experimental and theoretical studies have lately revealed that under-coordinated Pd-sites in the PdO(101) surface act as efficient centers for methane dissociation. Here, the density functional theory is used to explore the underlying reason for the low activation energy by systematically investigating a range of hypothetical metal-oxides in the PdO structure. Low activation energies are calculated for metal-oxides where the initial state is stabilized via reduced Pauli repulsion between the methane molecule and the site of dissociation. The low activation energy is found to be an atomic property and facile methane dissociation is predicted for single Pd atoms with appropriate ligands. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
  •  
45.
  • Vaqueiro-Contreras, Michelle, et al. (författare)
  • Powerful recombination centers resulting from reactions of hydrogen with carbon–oxygen defects in n-type Czochralski-grown silicon
  • 2017
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : John Wiley & Sons. - 1862-6254 .- 1862-6270. ; 11:8
  • Tidskriftsartikel (refereegranskat)abstract
    • It has been acknowledged for over 50 years that treatments with hydrogen can improve silicon semiconductor devices. In recent years, these have been used to an advantage in silicon solar cells reducing the loss of photo-generated carriers at the silicon surface or at the silicon interface with dielectrics. However, we have found that in some types of silicon the in-diffusion of hydrogen can result in the formation of powerful recombination centers composed of carbon, oxygen, and hydrogen which reduce the carrier lifetime and ultimately the efficiency of solar cells made from such material
  •  
46.
  • Vermang, Bart, et al. (författare)
  • Potential-induced optimization of ultra-thin rear surface passivated CIGS solar cells
  • 2014
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 8:11, s. 908-911
  • Tidskriftsartikel (refereegranskat)abstract
    • Ultra-thin Cu(In,Ga)Se-2 (CIGS) solar cells with an Al2O3 rear surface passivation layer between the rear contact and absorber layer frequently show a roll-over effect in the J-V curve, lowering the open circuit voltage (V-OC), short circuit current (J(SC)) and fill factor (FF), similar to what is observed for Na-deficient devices. Since Al2O3 is a well-known barrier for Na, this behaviour can indeed be interpreted as due to lack of Na in the CIGS absorber layer. In this work, applying an electric field between the backside of the soda lime glass (SLG) substrate and the SLG/rear-contact interface is investi-gated as potential treatment for such Na-deficient rear surface passivated CIGS solar cells. First, an electrical field of +50 V is applied at 85 degrees C, which increases the Na concentration in the CIGS absorber layer and the CdS buffer layer as measured by glow discharge optical emission spectroscopy (GDOES). Subsequently, the field polarity is reversed and part of the previously added Na is removed. This way, the J -V curve roll-over related to Na deficiency disappears and the V-OC (+25 mV), J(SC)(+2.3 mA/cm(2)) and FF (+13.5% absolute) of the rear surface passivated CIGS solar cells are optimized.
  •  
47.
  • Vähänissi, Ville, et al. (författare)
  • Physical mechanisms of boron diffusion gettering of iron in silicon
  • 2010
  • Ingår i: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlagsgesellschaft. - 1862-6254 .- 1862-6270. ; 4:5-6, s. 136-138
  • Tidskriftsartikel (refereegranskat)abstract
    • We have studied the boron diffusion gettering (BDG) of iron in single crystalline silicon. The results show that iron is gettered efficiently by electrically inactive boron, which leads to gettering efficiencies comparable to phosphorus diffusion gettering (PDG). In addition we discuss the different physical mechanisms behind BDG. We also consider the possibilities of using boron diffusion gettering in solar cell fabrication and discuss the role of boron and iron concentration in the optimization of gettering efficiency.
  •  
48.
  •  
49.
  • Zeng, Lunjie, 1983, et al. (författare)
  • The Effect of Bending Deformation on Charge Transport and Electron Effective Mass of p-doped GaAs Nanowires
  • 2019
  • Ingår i: Physica Status Solidi - Rapid Research Letetrs. - : Wiley. - 1862-6254 .- 1862-6270. ; 13:8
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The crystal and electronic structure of semiconductor nanowire systems have shown sensitive response to mechanical strain, enabling novel and improved electrical, and optoelectrical properties in nanowires by strain engineering. Here, the response of current–voltage (I–V) characteristics and band structure of individual p-doped GaAs nanowires to bending deformation is studied by in situ electron microscopy combined with theoretical simulations. The I–V characteristics of the nanowire change from linear to nonlinear as bending deformation is applied. The nonlinearity increases with strain. As opposed to the case of uniaxial strain in GaAs, the bending deformation does not give rise to a change in the band gap of GaAs nanowire according to in situ electron energy loss spectroscopy (EELS) measurements. Instead, the response to bending deformation can be explained by strain induced valence band shift, which results in an energy barrier for charge carrier transport along the nanowire. Moreover, the electron effective mass decreases as the strain changes from compressive to tensile across the GaAs nanowire in the bent region. Results from this study shed light on the complex interplay between lattice strain, band structure, and charge transport in semiconductor nanomaterials.
  •  
50.
  • Beckers, Manfred, et al. (författare)
  • Formation of basal plane fiber-textured Ti2AlN films on amorphous substrates
  • 2010
  • Ingår i: PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS. - : John Wiley and Sons, Ltd. - 1862-6254. ; 4:05-Jun, s. 121-123
  • Tidskriftsartikel (refereegranskat)abstract
    • The synthesis of fiber-textured Ti2AlN(0001) films on SiO2 was characterized by in-situ and ex-situ X-ray scattering and Rutherford backscattering spectrometry. Ti2AlN was formed by solid-state reaction between sequentially deposited Ti and AlN layers. A deposition at 275 degrees C yields a Ti(0001) out-of-plane orientation which is maintained for the following AlN(0001)/Ti(0001) layers. Annealing to 600 degrees C yields AlN decomposition and diffusion of Al and N into Ti, with consecutive transformation into (TiAlN)-Al-3(111) and Ti2AlN(0001) plus AlN residuals. Despite preferred Ti2AlN(0001) out-of-plane orientation, the in-plane distribution is random, as expected from the self-organized pseudo-epitaxial growth.
  •  
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