| 1. |
- Amin, Gul, et al.
(author)
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ZnO nanorods-polymer hybrid white light emitting diode grown on a disposable paper substrate
- 2011
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In: Physica Status Solidi. Rapid Research Letters. - : John Wiley and Sons, Ltd. - 1862-6254 .- 1862-6270. ; 5:2, s. 71-73
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Journal article (peer-reviewed)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. |
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| 3. |
- Brown, D. R., et al.
(author)
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Relating phase transition heat capacity to thermal conductivity and effusivity in Cu2Se
- 2016
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In: Physica Status Solidi - Rapid Research Letetrs. - : Wiley. - 1862-6254 .- 1862-6270. ; 10:8, s. 618-621
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Journal article (peer-reviewed)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.
(author)
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From the adiabatic theorem of quantum mechanics to topological states of matter
- 2013
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In: Physica Status Solidi. Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 7:1-2, s. 109-129
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Research review (peer-reviewed)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.
(author)
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Fast piezoresistive sensor and UV photodetector based on Mn-doped ZnO nanorods
- 2015
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In: Physica Status Solidi. Rapid Research Letters. - : John Wiley & Sons. - 1862-6254 .- 1862-6270. ; 9:1, s. 87-91
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Journal article (peer-reviewed)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.
(author)
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Epitaxial CVD growthof sp2-hybridized boron nitrideusing aluminum nitride as buffer layer
- 2011
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In: Physica Status Solidi. Rapid Research Letters. - : Wiley-VCH Verlagsgesellschaft. - 1862-6254 .- 1862-6270. ; 5:10-11, s. 397-399
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Journal article (peer-reviewed)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.
(author)
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Epitaxial TiC/SiC multilayers
- 2007
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In: Physica status solidi (RRL): rapid research letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 1:3, s. 113-115
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Journal article (peer-reviewed)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.
(author)
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Epitaxial Growth of CaMnO3-y Films on LaAlO3 (112 over bar 0) by Pulsed Direct Current Reactive Magnetron Sputtering
- 2022
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In: Physica Status Solidi. Rapid Research Letters. - : Wiley-V C H Verlag GMBH. - 1862-6254 .- 1862-6270. ; 16:4
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Journal article (peer-reviewed)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.
(author)
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Coherent acoustic phonon oscillations and transient critical point parameters of Ge from femtosecond pump‐probe ellipsometry
- 2022
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In: Physica Status Solidi - Rapid Research Letters. - : Wiley. - 1862-6254 .- 1862-6270. ; 16:7
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Journal article (peer-reviewed)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.
(author)
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Correlation-Driven Magnetic Frustration and Insulating Behavior of TiF 3
- 2024
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In: Physica Status Solidi - Rapid Research Letetrs. - 1862-6254 .- 1862-6270. ; 18:3
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Journal article (peer-reviewed)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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