| 1. |
- Anttu, Nicklas, et al.
(författare)
-
Drastically increased absorption in vertical semiconductor nanowire arrays: A non-absorbing dielectric shell makes the difference
- 2012
-
Ingår i: Nano Reseach. - : Springer Science and Business Media LLC. - 1998-0124 .- 1998-0000. ; 5:12, s. 863-874
-
Tidskriftsartikel (refereegranskat)abstract
- Enhanced absorption of especially long wavelength light is needed to enable the full potential of semiconductor nanowire (NW) arrays for optoelectronic applications. We show both experimentally and theoretically that a transparent dielectric shell (Al2O3 coating) can drastically improve the absorption of light in InAs NW arrays. With an appropriate thickness of the Al2O3 shell, we achieve four times stronger absorption in the NWs compared to uncoated NWs and twice as good absorption as when the dielectric completely fills the space between the NWs. We provide detailed theoretical analysis from a combination of full electrodynamic modeling and intuitive electrostatic approximations. This reveals how the incident light penetrates better into the absorbing NW core with increasing thickness of the dielectric shell until a resonant shell thickness is reached. We provide a simple description of how to reach this strongly absorbing resonance condition, making our results easy to apply for a broad wavelength range and a multifold of semiconductor and dielectric coating material combinations.
|
|
| 2. |
- Anttu, Nicklas, et al.
(författare)
-
Excitations of surface plasmon polaritons in double layer metal grating structures
- 2012
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:9
-
Tidskriftsartikel (refereegranskat)abstract
- We study the light scattering properties of double layer gratings (DLGs) made from Au on SiO2 substrates. It is found that surface plasmon polaritons (SPPs) can be excited in the DLGs for a separation of up to 150 nm between the two Au grating layers and the collective reflectance spectra exhibit a strong resonant peak and a closely lying dip as a result of the surface plasmon polariton excitations. It is also found that the angle-resolved specular reflectance spectra show a dip-peak pair structure, while the angle-resolved reflectance spectra of higher diffracted orders show a complementary peak-dip pair structure. Finally, operation of the DLGs for efficient wavelength demultiplexing is proposed and discussed in light of these results. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3690947]
|
|
| 3. |
- Borgström, Magnus, et al.
(författare)
-
Fabrication and characterization of AlP-GaP core-shell nanowires
- 2011
-
Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 324:1, s. 290-295
-
Tidskriftsartikel (refereegranskat)abstract
- We report on the particle assisted synthesis of core-shell AlP-GaP nanowires by use of metal-organic vapor phase epitaxy. The core-shell approach is chosen such as to stabilize the AlP which is highly sensitive to water. The nanowires were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. These nanowires have an indirect band-gap and form a type II staggered heterojunction. By designed capping of the AlP cores by GaP, we find the nanowires to be stable for more than a year. (C) 2011 Elsevier B.V. All rights reserved.
|
|
| 4. |
- Chen, Jianing, et al.
(författare)
-
Probing Strain in Bent Semiconductor Nanowires with Raman Spectroscopy.
- 2010
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 10:4, s. 1280-1286
-
Tidskriftsartikel (refereegranskat)abstract
- We present a noninvasive optical method to determine the local strain in individual semiconductor nanowires. InP nanowires were intentionally bent with an atomic force microscope and variations in the optical phonon frequency along the wires were mapped using Raman spectroscopy. Sections of the nanowires with a high curvature showed significantly broadened phonon lines. These observations together with deformation potential theory show that compressive and tensile strain inside the nanowires is the physical origin of the observed phonon energy variations.
|
|
| 5. |
- Fian, Alexander, et al.
(författare)
-
New Flexible Toolbox for Nanomechanical Measurements with Extreme Precision and at Very High Frequencies.
- 2010
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 10:Online August 26, 2010, s. 3893-3898
-
Tidskriftsartikel (refereegranskat)abstract
- We show that the principally two-dimensional (2D) scanning tunneling microscope (STM) can be used for imaging of 1D micrometer high free-standing nanowires. We can then determine nanowire megahertz resonance frequencies, image their top-view 2D resonance shapes, and investigate axial stress on the nanoscale. Importantly, we demonstrate the extreme sensitivity of electron tunneling even at very high frequencies by measuring resonances at hundreds of megahertz with a precision far below the angstrom scale.
|
|
| 6. |
- Gisselsson Nord, David, et al.
(författare)
-
When the genome plays dice: circumvention of the spindle assembly checkpoint and near-random chromosome segregation in multipolar cancer cell mitoses.
- 2008
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:4
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Normal cell division is coordinated by a bipolar mitotic spindle, ensuring symmetrical segregation of chromosomes. Cancer cells, however, occasionally divide into three or more directions. Such multipolar mitoses have been proposed to generate genetic diversity and thereby contribute to clonal evolution. However, this notion has been little validated experimentally. PRINCIPAL FINDINGS: Chromosome segregation and DNA content in daughter cells from multipolar mitoses were assessed by multiphoton cross sectioning and fluorescence in situ hybridization in cancer cells and non-neoplastic transformed cells. The DNA distribution resulting from multipolar cell division was found to be highly variable, with frequent nullisomies in the daughter cells. Time-lapse imaging of H2B/GFP-labelled multipolar mitoses revealed that the time from the initiation of metaphase to the beginning of anaphase was prolonged and that the metaphase plates often switched polarity several times before metaphase-anaphase transition. The multipolar metaphase-anaphase transition was accompanied by a normal reduction of cellular cyclin B levels, but typically occurred before completion of the normal separase activity cycle. Centromeric AURKB and MAD2 foci were observed frequently to remain on the centromeres of multipolar ana-telophase chromosomes, indicating that multipolar mitoses were able to circumvent the spindle assembly checkpoint with some sister chromatids remaining unseparated after anaphase. Accordingly, scoring the distribution of individual chromosomes in multipolar daughter nuclei revealed a high frequency of nondisjunction events, resulting in a near-binomial allotment of sister chromatids to the daughter cells. CONCLUSION: The capability of multipolar mitoses to circumvent the spindle assembly checkpoint system typically results in a near-random distribution of chromosomes to daughter cells. Spindle multipolarity could thus be a highly efficient generator of genetically diverse minority clones in transformed cell populations.
|
|
| 7. |
- Hilner, Emelie, et al.
(författare)
-
Direct Atomic Scale Imaging of III-V Nanowire Surfaces.
- 2008
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 8:11, s. 3978-3982
-
Tidskriftsartikel (refereegranskat)abstract
- We have succeeded in direct atomic scale imaging of the exterior surfaces of III-V nanowires by scanning tunneling microscopy (STM). By using atomic hydrogen, we expose the crystalline surfaces of InAs nanowires with regular InP segments in vacuum while retaining the wire morphology. We show images with atomic resolution of the two major types of InAs wurtzite nanowire surface facets and scanning tunneling spectroscopy (STS) data. Ab initio calculations of the lowest energy surface structures and simulated STM images, agree very well with experiments.
|
|
| 8. |
- Hjort, Martin, et al.
(författare)
-
Surface Chemistry, Structure, and Electronic Properties from Microns to the Atomic Scale of Axially Doped Semiconductor Nanowires.
- 2012
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851.
-
Tidskriftsartikel (refereegranskat)abstract
- Using both synchrotron-based photoemission electron microscopy/spectroscopy and scanning tunneling microscopy/spectroscopy, we obtain a complete picture of the surface composition, morphology, and electronic structure of InP nanowires. Characterization is done at all relevant length scales from micrometer to nanometer. We investigate nanowire surfaces with native oxide and molecular adsorbates resulting from exposure to ambient air. Atomic hydrogen exposure at elevated temperatures which leads to the removal of surface oxides while leaving the crystalline part of the wire intact was also studied. We show how surface chemical composition will seriously influence nanowire electronic properties. However, opposite to, for example, Ge nanowires, water or sulfur molecules adsorbed on the exterior oxidized surfaces are of less relevance. Instead, it is the final few atomic layers of the oxide which plays the most significant role by strongly negatively doping the surface. The InP nanowires in air are rather insensitive to their chemical surroundings in contrast to what is often assumed for nanowires. Our measurements allow us to draw a complete energy diagram depicting both band gap and differences in electron affinity across an axial nanowire p-n junction. Our findings thus give a robust set of quantitative values relating surface chemical composition to specific electronic properties highly relevant for simulating the performance of nanoscale devices.
|
|
| 9. |
- Håkanson, Ulf, et al.
(författare)
-
Coupling of plasmonic nanoparticles to their environments in the context of van der Waals-Casimir interactions
- 2008
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 77:15, s. 9-155408
-
Tidskriftsartikel (refereegranskat)abstract
- We present experiments in which the interaction of a single gold nanoparticle with glass substrates or with another gold particle can be tuned by in situ control of their separations using scanning probe technology. We record the plasmon resonances of the coupled systems as a function of the polarization of the incident field and the particle position. The distinct spectral changes of the scattered light from the particle pair are in good agreement with the outcome of finite-difference time-domain calculations. We believe that our experimental technique holds promise for the investigation of the van der Waals-Casimir-type interactions between nanoscopic neutral bodies.
|
|
| 10. |
- Håkanson, Ulf, et al.
(författare)
-
Electric field effects in single semiconductor quantum dots observed by scanning tunneling luminescence
- 2003
-
Ingår i: Journal of Vacuum Science and Technology B. - : American Vacuum Society. - 1520-8567. ; 21:6, s. 2344-2347
-
Tidskriftsartikel (refereegranskat)abstract
- Scanning tunneling microscopy (STM) and scanning tunneling luminescence were used to correlate the topography with the emission spectra from individual self-assembled, InP quantum dots (QDs). We have investigated in detail how the electric field induced by the STM tip affects the emission from the QDs. This was done when exciting a QD, by altering the bias for constant current, by altering the current for constant bias, or by changing the tip position. An increased bias (increased electric field) leads to Stark shift of the QD emission, whereas a larger tunneling current results in state filling of the emission. Furthermore, when exciting the QD, the position of the STM tip is shown to have large effects on the QD luminescence.
|
|
| 11. |
- Håkanson, Ulf, et al.
(författare)
-
Luminescence polarization of ordered GaInP/InP islands
- 2003
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 82:4, s. 627-629
-
Tidskriftsartikel (refereegranskat)abstract
- The luminescence polarization properties of GaInP islands have been investigated. The islands, which form during overgrowth of InP quantum dots, were studied using scanning tunneling luminescence (STL) and photoluminescence (PL). STL from these islands shows emission at an energy below the main emission peak of the bulk GaInP. The linear PL polarization anisotropy was measured at low temperature, for which the emission from the islands shows high polarization anisotropy. The intensity maximum for the emission occurs for light polarized parallel to the elongation of the islands. The observed linear PL polarization anisotropy indicates the presence of highly ordered domains of GaInP in the islands. (C) 2003 American Institute of Physics.
|
|
| 12. |
- Håkanson, Ulf, et al.
(författare)
-
Nano-aperture fabrication for single quantum dot spectroscopy
- 2003
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 14:6, s. 675-679
-
Tidskriftsartikel (refereegranskat)abstract
- We present a simple and controllable method for fabricating nano-apertures in a metal film using polystyrene nano-spheres as masks during the metal evaporation. We show how the processing conditions used during deposition of the spheres such as spin velocity, nano-sphere concentration and a reduction of the surface tension interplay and control the distribution of spheres. The fabrication method is ideal for luminescence studies by isolating individual nanometre-sized objects, which is exemplified by photoluminescence spectroscopy of single self-assembled Stranski-Krastanow quantum dots.
|
|
| 13. |
- Håkanson, Ulf, et al.
(författare)
-
Photon mapping of quantum dots using a scanning tunneling microscope
- 2002
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 81:23, s. 4443-4445
-
Tidskriftsartikel (refereegranskat)abstract
- Scanning tunneling microscopy (STM) and scanning tunneling luminescence (STL) have been used to investigate the geometric and optical properties of individual self-assembled InP quantum dots overgrown with a thin layer of GaInP. STL spectra and monochromatic photon maps were used to correlate the surface topography with the optical properties of single quantum dots. We find a spatial resolution of about 10 nm in the photon maps. Theoretical emission spectra were calculated by six-band k.p theory using a realistic shape of the dot as well as of the cap layer. The calculated emission spectrum of a single dot is in good agreement with the experimental findings. (C) 2002 American Institute of Physics.
|
|
| 14. |
- Håkanson, Ulf, et al.
(författare)
-
Photon mapping of single quantum dots by scanning tunneling microscopy induced luminescence spectroscopy
- 2002
-
Ingår i: 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science.
-
Konferensbidrag (refereegranskat)abstract
- Scanning tunneling microscopy induced luminescence (STML) has been used to investigate individual self-assembled InP quantum dots overgrown with GaInP. We will present results correlating the surface morphology with the optical properties of single dots. In particular, the strain induced energy-shift of the dot emission with increasing cap layer thickness and its relation to the overgrowth will be discussed. Effects of the dots on the properties of the overgrown GaInP will also be treated. STML spectra and monochromatic photon maps are compared with results from photoluminescence and transmission electron microscopy measurements. Furthermore, a comparison with theoretical calculations is made
|
|
| 15. |
- Håkanson, Ulf, et al.
(författare)
-
Quantum-dot-induced ordering in GaxIn1-xP/InP islands
- 2002
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 66:23
-
Tidskriftsartikel (refereegranskat)abstract
- Thin layers of GaxIn1-xP grown on top of self-assembled InP quantum dots has been studied using transmission electron microscopy (TEM), scanning tunneling microscopy (STM), and low-temperature scanning tunneling luminescence (STL). STM reveals that the overgrowth is highly uneven, in which elongated GaxIn1-xP islands covering the dots are formed. TEM and high-spatial-resolution STL show that the quantum dots locally induce domains with higher degree of ordering in the islands. The luminescence from these domains is observed as a strong GaxIn1-xP peak at an energy below the emission from the GaxIn1-xP barrier material.
|
|
| 16. |
- Håkanson, Ulf
(författare)
-
Scanning Tunneling Microscopy Induced Luminescence Studies of Semiconductor Nanostructures
- 2003
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis treats scanning tunneling luminescence (STL) investigations of semiconductor nanostructures. The STL technique combines scanning tunneling microscopy (STM) with detection of photons, induced by the tunneling electrons. The high spatial resolution in STM and the local excitation allow for optical investigations on the nanometer-scale. The work concerns design and implementation of an optical detection system used for STL studies of single InP quantum dots (QDs) overgrown with thin layers of GaInP. Constant current imaging together with STL spectra and monochromatic photon mapping were used to correlate the surface topography with the optical properties of the QDs. It was found that the QDs act as seeds for the GaInP overgrowth, where elongated GaInP islands are formed. The emission from single QDs was observed to be shifted towards higher energies with increasing cap layer thickness, which by multi-band k.p theory was determined to be induced by strain. The geometry of the overgrowth was realistically modelled in the calculations, using data from STM and transmission electron microscopy. Theoretical emission energies were also calculated, which are in good agreement with the experimental results. Studies of the GaInP islands showed that the InP QDs locally induce domains in the islands with high degree of ordering in the GaInP. The emission from these domains was found to occur at an energy below the emission from the GaInP barrier material. High polarization anisotropy for the island luminescence was observed by photoluminescence measurements, in which maximum emission intensity was detected for light polarized parallel to the elongation of the islands.
|
|
| 17. |
- Håkanson, Ulf, et al.
(författare)
-
Single InP/GaInP quantum dots studied by scanning tunneling microscopy and scanning tunneling microscopy induced luminescence
- 2002
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 80:3, s. 494-496
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied the optical and structural properties of single, self-assembled InP quantum dots (QDs) overgrown with nominally 5 nm of GaInP, using an ultrahigh-vacuum scanning tunneling microscope (STM) operating at low temperatures. The STM is combined with an optical detection system, which allows us to detect the emission from individual quantum dots with high spatial resolution. We find that the InP QDs act as nucleation points for the GaInP overgrowth, where the strain induced by the overlayer give rise to a QD emission around 1.46 eV. (C) 2002 American Institute of Physics.
|
|
| 18. |
- Håkanson, Ulf, et al.
(författare)
-
Ultrahigh vacuum scanning probe investigations of metal induced void formation in SiO2/Si(111))
- 2002
-
Ingår i: JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 20:1, s. 226-229
-
Konferensbidrag (refereegranskat)abstract
- Using scanning electron microscopy guidance, atomically resolved scanning tunneling microscopy investigations inside openings formed during the decomposition of a thick SiO2 film on a Si(111) surface have been performed. We report, for the first time, the presence of Ni atoms inside self-formed openings. The SiO2 decomposition as a function of annealing temperature and time was studied. By comparing self-formed and lithographically designed openings in the SiO2 layer we have shown that Ni contamination of the SiO2/Si(111) has a profound effect on the formation of self-induced lateral oxide openings. (C) 2002 American Vacuum Society.
|
|
| 19. |
- Johansson, Mikael, et al.
(författare)
-
Correlation between overgrowth morphology and optical properties of single self-assembled InP quantum dots
- 2003
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 68:12
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied the early stages of GaInP overgrowth on InP quantum dots (QD's) experimentally and theoretically. A direct correlation between the surface morphology and the optical properties of individual InP QD's is made using scanning tunneling microscopy (STM) and scanning tunneling luminescence. The geometric structure of the islands is further investigated using cross-sectional transmission electron microscopy (TEM). The overgrowth occurs in three stages; initially the InP QD's act as seeding points for the overgrowth, where the GaInP grows laterally from the side facets of the QD. The growth occurs preferentially in the [110] direction and elongated GaInP/InP islands are formed. As the overgrowth continues the islands increase laterally in size and GaInP also starts to grow between the islands, but not covering the top of the InP QD's. The growth of GaInP on top of the QD's commences once the islands have begun to coalesce. Using a model based on the STM and TEM results the electronic structures of the QD's have been calculated by eight-band k.p theory. The calculations are in good agreement with the experimental results. Our findings unravel the details of the strain induced energy shift of the QD luminescence previously reported [Pistol , Appl. Phys. Lett. 67, 1438 (1995)].
|
|
| 20. |
|
|
| 21. |
- Lundberg, Gisela, et al.
(författare)
-
Binomial mitotic segregation of MYCN-carrying double minutes in neuroblastoma illustrates the role of randomness in oncogene amplification.
- 2008
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:8
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Amplification of the oncogene MYCN in double minutes (DMs) is a common finding in neuroblastoma (NB). Because DMs lack centromeric sequences it has been unclear how NB cells retain and amplify extrachromosomal MYCN copies during tumour development. PRINCIPAL FINDINGS: We show that MYCN-carrying DMs in NB cells translocate from the nuclear interior to the periphery of the condensing chromatin at transition from interphase to prophase and are preferentially located adjacent to the telomere repeat sequences of the chromosomes throughout cell division. However, DM segregation was not affected by disruption of the telosome nucleoprotein complex and DMs readily migrated from human to murine chromatin in human/mouse cell hybrids, indicating that they do not bind to specific positional elements in human chromosomes. Scoring DM copy-numbers in ana/telophase cells revealed that DM segregation could be closely approximated by a binomial random distribution. Colony-forming assay demonstrated a strong growth-advantage for NB cells with high DM (MYCN) copy-numbers, compared to NB cells with lower copy-numbers. In fact, the overall distribution of DMs in growing NB cell populations could be readily reproduced by a mathematical model assuming binomial segregation at cell division combined with a proliferative advantage for cells with high DM copy-numbers. CONCLUSION: Binomial segregation at cell division explains the high degree of MYCN copy-number variability in NB. Our findings also provide a proof-of-principle for oncogene amplification through creation of genetic diversity by random events followed by Darwinian selection.
|
|
| 22. |
|
|
| 23. |
- Nüske, Ralf, et al.
(författare)
-
Transforming graphite to nanoscale diamonds by a femtosecond laser pulse
- 2012
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:4
-
Tidskriftsartikel (refereegranskat)abstract
- Formation of cubic diamond from graphite following irradiation by a single, intense, ultra-short laser pulse has been observed. Highly oriented pyrolytic graphite (HOPG) samples were irradiated by a 100 fs pulse with a center wavelength of 800 nm. Following laser exposure, the HOPG samples were studied using Raman spectroscopy of the sample surface. In the laser-irradiated areas, nanoscale cubic diamond crystals have been formed. The exposed areas were also studied using grazing incidence x-ray powder diffraction showing a restacking of planes from hexagonal graphite to rhombohedral graphite. (C) 2012 American Institute of Physics. [doi:10.1063/1.3678190]
|
|
| 24. |
- Persson, Jonas, et al.
(författare)
-
Strain effects on individual quantum dots: Dependence of cap layer thickness
- 2005
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 72:8
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied the effects of strain on individual self-assembled quantum dots (QDs) exemplified by InP dots embedded in GaInP. The quantum dot sample was etched from the top and in this way the amount of capping material was reduced. In a sequence of etch cycles, the cap layer was thinned, and the photoluminescence from several individual QDs could be followed as a function of cap layer thickness. The evolution of the emission spectra clearly depended on the quantum dot size. We interpret this as arising from differences in the aspect ratio for quantum dots of different sizes. The influence of the capping layer, for different QD geometries, was modeled using deformation potential theory with the strain calculated using a full three-dimensional linear elasticity model. The results agree well with the experimental observations.
|
|
| 25. |
|
|
| 26. |
- Zhang, Shunping, et al.
(författare)
-
Chiral Surface Plasmon Polaritons on Metallic Nanowires
- 2011
-
Ingår i: Physical Review Letters. - 1079-7114. ; 107:9
-
Tidskriftsartikel (refereegranskat)abstract
- Chiral surface plasmon polaritons (SPPs) can be generated by linearly polarized light incident at the end of a nanowire, exciting a coherent superposition of three specific nanowire waveguide modes. Images of chiral SPPs on individual nanowires obtained from quantum dot fluorescence excited by the SPP evanescent field reveal the chirality predicted in our theoretical model. The handedness and spatial extent of the helical periods of the chiral SPPs depend on the input polarization angle and nanowire diameter as well as the dielectric environment. Chirality is preserved in the free-space output wave, making a metallic nanowire a broad bandwidth subwavelength source of circular polarized photons.
|
|
| 27. |
- ZhiQiang, Guan, et al.
(författare)
-
Surface-enhanced Raman scattering on dual-layer metallic grating structures
- 2010
-
Ingår i: Chinese Science Bulletin. - : Springer Science and Business Media LLC. - 1001-6538 .- 1861-9541. ; 55:24, s. 2643-2648
-
Tidskriftsartikel (refereegranskat)abstract
- Dual-layer Metallic grating (DMG) structures as surface-enhanced Raman scattering (SERS) substrates are studied using benzenethiol as the probe analyte. The DMG structure consists of a SiO2 grating and 100-nm-thick gold coating layers. An enhancement factor of 10(5) is achieved by optimizing the SiO2 grating height within the range from 165 to 550 nm. The enhancement factor dependence on the SiO2 grating height is due to the surface plasmon excitation, which is dependent on the polarization of the incident light, and confirmed by finite difference time domain simulations. This study demonstrates the advantages of high uniformity, reproducibility and sensitivity in the DMG structures for SERS applications.
|
|
