The Experts below are selected from a list of 274635 Experts worldwide ranked by ideXlab platform
X Y Hou - One of the best experts on this subject based on the ideXlab platform.
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field emission enhancement by the Quantum Structure in an ultrathin multilayer planar cold cathode
Applied Physics Letters, 2008Co-Authors: Ruzhi Wang, Hui Yan, Baigeng Wang, Xingwang Zhang, X Y HouAbstract:Field electron emission (FE) from an ultrathin multilayer planar cold cathode (UMPC) including a Quantum well Structure has been both experimentally and theoretically investigated. We found that by tuning the energy levels of UMPC, the FE characteristic can be evidently improved, which is unexplained by conventional FE mechanism. FE emission mechanism, dependent on the Quantum Structure effect, which supplies a favorable location of electron emission and enhances tunneling ability, has been presented to expound the notable amelioration. An approximate formula, brought forward, can predict the Quantum FE enhancement, in which the theoretical prediction is close to the experimental result.
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field electron emission mechanism in an ultrathin multilayer planar cold cathode
arXiv: Mesoscale and Nanoscale Physics, 2006Co-Authors: Rui Wang, Baigeng Wang, Hugen Yan, X W Zhang, X Y HouAbstract:Field electron emission from an ultrathin multilayer planar cold cathode (UMPC) including Quantum well Structure has been both experimentally and theoretically investigated. We found that only tuning the energy levels of UMPC the field electron emission (FE) characteristic can be evidently improved, which is unexplained by the conventional FE mechanism. Field electron emission mechanism dependent on the Quantum Structure effect, which supplies a favorable location of electron emission and enhances tunneling ability, has been presented to expound the notable amelioration. An approximate formula brought forward can predict the Quantum FE enhancement, which the theoretical prediction is close to the experimental result.
Hongqi Xu - One of the best experts on this subject based on the ideXlab platform.
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coulomb blockade from the shell of an inp inas core shell nanowire with a triangular cross section
Applied Physics Letters, 2019Co-Authors: D J O Goransson, Magnus Heurlin, B Dalelkhan, Simon Abay, Maria E Messing, V F Maisi, Magnus T Borgstrom, Hongqi XuAbstract:We report on growth of InP-InAs core-shell nanowires and demonstration of the formation of single Quantum Structures, which show the Coulomb blockade effect, over entire lengths of the nanowires. The core-shell nanowires are grown by a selective area growth technique via metal-organic vapor phase epitaxy. The as-grown core-shell nanowires are found to be of wurtzite crystals. The InP cores have a hexagonal cross section, while the InAs shells are grown preferentially on specific { 1 1 ¯ 00} facets, leading to the formation of the core-shell nanowires with an overall triangular cross section. The grown core-shell nanowires are transferred onto a Si/SiO2 substrate and then contacted by several narrow metal electrodes. Low-temperature transport measurements show the Coulomb-blockade effect. We analyze the measured gate capacitance and single electron charging energy of the devices and demonstrate that a Quantum Structure which shows the Coulomb blockade effect of a many-electron Quantum dot is formed over the full length of a single core-shell nanowire and consists of the entire InAs shell in the nanowire.We report on growth of InP-InAs core-shell nanowires and demonstration of the formation of single Quantum Structures, which show the Coulomb blockade effect, over entire lengths of the nanowires. The core-shell nanowires are grown by a selective area growth technique via metal-organic vapor phase epitaxy. The as-grown core-shell nanowires are found to be of wurtzite crystals. The InP cores have a hexagonal cross section, while the InAs shells are grown preferentially on specific { 1 1 ¯ 00} facets, leading to the formation of the core-shell nanowires with an overall triangular cross section. The grown core-shell nanowires are transferred onto a Si/SiO2 substrate and then contacted by several narrow metal electrodes. Low-temperature transport measurements show the Coulomb-blockade effect. We analyze the measured gate capacitance and single electron charging energy of the devices and demonstrate that a Quantum Structure which shows the Coulomb blockade effect of a many-electron Quantum dot is formed ove...
Zhiming Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of rapid thermal annealing on the optical properties of strain free Quantum ring solar cells
Nanoscale Research Letters, 2013Co-Authors: Zhiming Wang, V G Dorogan, Jihoon Lee, Yuriy I Mazur, Eunsoo Kim, Gregory J SalamoAbstract:Strain-free GaAs/Al0.33Ga0.67As Quantum rings are fabricated by droplet epitaxy. Both photoresponse and photoluminescence spectra confirm optical transitions in Quantum rings, suggesting that droplet epitaxial nanomaterials are applicable to intermediate band solar cells. The effects of post-growth annealing on the Quantum ring solar cells are investigated, and the optical properties of the solar cells with and without thermal treatment are characterized by photoluminescence technique. Rapid thermal annealing treatment has resulted in the significant improvement of material quality, which can be served as a standard process for Quantum Structure solar cells grown by droplet epitaxy.
Keqiu Chen - One of the best experts on this subject based on the ideXlab platform.
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Heat transport in multilayer abrupt graphene junctions modulated with convexity-shaped Quantum Structure
EPL (Europhysics Letters), 2012Co-Authors: Xiao-fang Peng, Xin-jun Wang, Li-qun Chen, Keqiu ChenAbstract:By using the force-constant and elastic wave continuum models, we investigate the ballistic phonon transport and thermal conductance in multilayer zigzag graphene nanoribbon junctions modulated with convexity-shaped Quantum Structures at low temperatures. The results show that the convexity-shaped (T-shaped or H-shaped) Quantum Structure can enhance thermal conductance at very low temperatures. The enhancement originates from the increased attenuation length of the evanescent modes in convexity-shaped Quantum Structures. A brief analysis of these results is given.
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Thermal transport associated with ballistic phonons in asymmetric Quantum Structures
Frontiers of Physics in China, 2009Co-Authors: Zong-liang Liu, Keqiu ChenAbstract:Using the scattering matrix method, we investigate the thermal conductance associated with ballistic phonons at low temperatures in asymmetric Quantum Structures. The results show that when the Structure is an ideal Quantum wire, the universal value π 2 κ B 2 (3h) can be observed at very low temperatures. However, for asymmetric Quantum Structure, the thermal conductance is less than the universal value π 2 κ B 2 (3h), even at T → 0. The results also show that the thermal conductance is strongly dependent on the transport direction. The rectification effect can be observed in the asymmetric Structure and can be adjusted by changing the structural parameters. A brief analysis of these results is given.
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acoustic phonon mode splitting behavior of an asymmetric y branch three terminal junction
Applied Physics Letters, 2004Co-Authors: Wenxia Li, Keqiu Chen, Wenhui Duan, Jian Wu, Binglin GuAbstract:The acoustic phonon transport through an asymmetric y-branch semiconductor Quantum Structure is investigated by use of the scattering-matrix method. It is found that the Quantum Structure exhibits mode-splitting behavior, resonant transmission, and the noninteger quantized thermal conductance at very low temperatures. The thermal transport behavior sensitively depends on the geometric configuration of the Structure. Our work suggests that such a y-branch Structure with specific structural parameters could be used as a splitter of phonon modes.
Gregory J Salamo - One of the best experts on this subject based on the ideXlab platform.
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Site-controlled formation of InGaAs Quantum nanoStructures-Tailoring the dimensionality and the Quantum confinement
Nano Research, 2013Co-Authors: Baolai Liang, Yuriy I Mazur, Gregory J Salamo, Ping-show Wong, Thai Tran, Vitaliy G. Dorogan, Morgan E. Ware, Chih-kang Shih, Diana L. HuffakerAbstract:We report on InGaAs Quantum disks (QDks) controllably formed on the top (001) facet of nano-patterned GaAs pyramidal platforms. The QDks exhibit pyramidal shape with special facets and varied dimensions, depending on the GaAs pyramidal buffer and the amount of InGaAs deposited. The formation of QDks is explained by the overgrowth of an InGaAs layer and thereafter coalescence of small InGaAs islands. Photoluminescence (PL) characteristics of ensemble QDks and exciton features of individual QDks together demonstrate that we may achieve a transition from zero-dimensional (0D) to two-dimensional (2D) Quantum Structure with increasing QDk size. This transition provides the flexibility to continuously tailor the dimensionality and subsequently the Quantum confinement of semiconductor nanoStructures via site-controlled self-assembled epitaxy for device applications based on single Quantum Structures.
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effects of rapid thermal annealing on the optical properties of strain free Quantum ring solar cells
Nanoscale Research Letters, 2013Co-Authors: Zhiming Wang, V G Dorogan, Jihoon Lee, Yuriy I Mazur, Eunsoo Kim, Gregory J SalamoAbstract:Strain-free GaAs/Al0.33Ga0.67As Quantum rings are fabricated by droplet epitaxy. Both photoresponse and photoluminescence spectra confirm optical transitions in Quantum rings, suggesting that droplet epitaxial nanomaterials are applicable to intermediate band solar cells. The effects of post-growth annealing on the Quantum ring solar cells are investigated, and the optical properties of the solar cells with and without thermal treatment are characterized by photoluminescence technique. Rapid thermal annealing treatment has resulted in the significant improvement of material quality, which can be served as a standard process for Quantum Structure solar cells grown by droplet epitaxy.