| 1. |
- Liang, D., et al.
(author)
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Electronic and excitonic properties of two-dimensional and bulk InN crystals
- 2017
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 7:67, s. 42455-42461
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Journal article (peer-reviewed)abstract
- Motivated by potential extensive applications in nanoelectronics devices of III-Vmaterials, we calculate the structural and optoelectronic properties of two-dimensional (2D) InN as well as its three-dimensional (3D) counterparts by using density functional theory (DFT). Compared with the 3D form, the In-N bonding in the 2D InN layer is stronger in terms of the shorter bond length, and the formation of the 2D one is higher in terms of the lower cohesive energy. The bandgap of monolayer InN is 0.31 eV at PBE level and 2.02 eV at GW(0) level. By many-body GW(0) and BSE within RPA calculations, monolayer InN presents an exciton binding energy of 0.12 eV. The fundamental bandgap increases along with layer reduction and is converted from direct (0.7-0.9 eV) in bulk InN to indirect (2.02 eV) in monolayer InN. Under biaxial compressive strain, the bandgap of 2D-InN can be further tuned from indirect to direct.
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| 2. |
- Wang, L, et al.
(author)
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Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application
- 2017
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In: Crystals. - : MDPI AG. - 2073-4352. ; 7:3, s. Article no 63 -
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Research review (peer-reviewed)abstract
- Dilute bismide in which a small amount of bismuth is incorporated to host III-Vs is the least studied III-V compound semiconductor and has received steadily increasing attention since 2000. In this paper, we review theoretical predictions of physical properties of bismide alloys, epitaxial growth of bismide thin films and nanostructures, surface, structural, electric, transport and optic properties of various binaries and bismide alloys, and device applications.
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| 3. |
- Liang, D., et al.
(author)
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Composition Dependence of Structural and Electronic Properties of Quaternary InGaNBi
- 2019
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In: Nanoscale Research Letters. - : Springer Science and Business Media LLC. - 1556-276X .- 1931-7573. ; 14
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Journal article (peer-reviewed)abstract
- To realize feasible band structure engineering and hence enhanced luminescence efficiency, InGaNBi is an attractive alloy which may be exploited in photonic devices of visible light and mid-infrared. In present study, the structural, electronic properties such as bandgap, spin-orbit splitting energy, and substrate strain of InGaNBi versus In and Bi compositions are studied by using first-principles calculations. The lattice parameters increase almost linearly with increasing In and Bi compositions. By bismuth doping, the quaternary InGaNBi bandgap could cover a wide energy range from 3.273 to 0.651 eV for Bi up to 9.375% and In up to 50%, corresponding to the wavelength range from 0.38-1.9 µm. The calculated spin-orbit splitting energy are about 0.220 eV for 3.125%, 0.360 eV for 6.25%, and 0.600 eV for 9.375% Bi, respectively. We have also shown the strain of InGaNBi on GaN; it indicates that through adjusting In and Bi compositions, InGaNBi can be designed on GaN with an acceptable strain.
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| 4. |
- Liang, D., et al.
(author)
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Structural, electronic, vibrational and optical properties of Bi-n clusters
- 2017
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In: Modern Physics Letters B. - : World Scientific Pub Co Pte Lt. - 0217-9849 .- 1793-6640. ; 31:28
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Journal article (peer-reviewed)abstract
- The neutral, anionic and cationic bismuth clusters with the size n up to 14 are investigated by using B3LYP functional within the regime of density functional theory and the LAN2DZ basis set. By analysis of the geometries of the Bin (n = 2-14)clusters, where cationic and anionic bismuth clusters are largely similar to those of neutral ones, a periodic effect by adding units with one to four atoms into smaller cluster to form larger cluster is drawn for the stable structures of bismuth clusters. An even odd alteration is shown for the properties of the clusters, such as the calculated binding energies and dissociation energies, as well as frontier orbital energies, electron affinities, ionization energies. All the properties indicate that the Bi-4 cluster is the most possible existence in bismuth-containing materials, which supports the most recent experiment. The orbital compositions, infrared and Raman activities and the ultraviolet absorption of the most possible tetramer bismuth cluster are given in detail to reveal the periodic tendency of adding bismuth atoms and the stability of tetramer bismuth cluster.
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| 5. |
- Liang, D., et al.
(author)
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Tunable band gaps in stanene/MoS2 heterostructures
- 2017
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In: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 52:10, s. 5799-5806
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Journal article (peer-reviewed)abstract
- First-principles calculations have been performed to investigate the geometric and electronic properties of stanene layer paired with monolayer MoS2 substrate with van der Waals corrections. It is found that the stanene can absorb on the monolayer MoS2 substrate forming stanene/MoS2 heterostructures, indicating a weak interface interaction. The Dirac point of stanene is still preserved on MoS2 substrate, and the band gap is opened about 67 meV due to the influence of the substrate. Moreover, the band gap is able to be effectively modulated under an external strain and a perpendicular electric field. These results are helpful for exploring the tunability of the electronic properties of stanene absorbed on semiconducting substrate.
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| 6. |
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| 7. |
- Lu, P. F., et al.
(author)
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Closing the bandgap for III-V nitrides toward mid-infrared and THz applications
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:1, s. Art. no 10594-
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Journal article (peer-reviewed)abstract
- A theoretical study of InNBi alloy by using density functional theory is presented. The results show non-linear dependence of the lattice parameters and bulk modulus on Bi composition. The formation energy and thermodynamic stability analysis indicate that the InNBi alloy possesses a stable phase over a wide range of intermediate compositions at a normal growth temperature. The bandgap of InNBi alloy in Wurtzite (WZ) phase closes for Bi composition higher than 1.5625% while that in zinc-blende (ZB) phase decreases significantly at around 356 meV/%Bi. The Bi centered ZB InNBi alloy presents a change from a direct bandgap to an indirect bandgap up to 1.5625% Bi and then an oscillates between indirect bandgap and semi-metallic for 1.5625% to 25% Bi and finally to metallic for higher Bi compositions. For the same Bi composition, its presence in cluster or uniform distribution has a salient effect on band structures and can convert between direct and indirect bandgap or open the bandgap from the metallic gap. These interesting electronic properties enable III-nitride closing the bandgap and make this material a good candidate for future photonic device applications in the mid-infrared to THz energy regime.
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| 8. |
- Lu, P. F., et al.
(author)
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Quasiparticle and optical properties of strained stanene and stanane
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:1, s. 8-
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Journal article (peer-reviewed)abstract
- Quasiparticle band structures and optical properties of two dimensional stanene and stanane (fully hydrogenated stanene) are studied by the GW and GW plus Bethe-Salpeter equation (GW-BSE) approaches, with inclusion of the spin-orbit coupling (SOC). The SOC effect is significant for the electronic and optical properties in both stanene and stanane, compared with their group IV-enes and IV-anes counterparts. Stanene is a semiconductor with a quasiparticle band gap of 0.10 eV. Stanane has a sizable band gap of 1.63 eV and strongly binding exciton with binding energy of 0.10 eV. Under strain, the quasiparticle band gap and optical spectrum of both stanene and stanane are tunable.
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| 9. |
- Sun, Yifan, et al.
(author)
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Sensitive parameters affecting dark current characteristics of SCD
- 2021
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 12061
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Conference paper (peer-reviewed)abstract
- The sensitive parameters affecting the dark current characteristics are further studied by using InAs/GaSb type II superlattice (T2SL) pBpp structure long wavelength Infrared photodetectors. Generation of recombination (G-R), surface leakage current and tunneling current are the main components of dark current. Using pBpp structure can suppress them effectively, thereby decreasing dark current. Based on the k · p method, the band structure of InAs/GaSb T2SL and InAs/AlSb T2SL can be obtained by solving the 8-band k · p model. We have calculated different doping levels of pBpp detector and different layer thicknesses of pBpp detector. For pBpp device, we consider the dark current for different contact layer doping and different absorber layer doping. We also study the influence of different contact layer thicknesses and different absorber layer thicknesses on dark current. The dark current of pBpp detector is dominant by tunneling current at low temperature, and diffusion is the main limiting mechanism in dark current at high temperature, for barrier layer inhibits generation-recombination contribution. Eventually, the dark current of a pBpp structure has been calculated for versus voltage at 77 K.
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| 10. |
- Wang, Shu Min, 1963, et al.
(author)
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Phosphorus and Nitrogen Containing Dilute Bismides
- 2019
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In: Springer Series in Materials Science. - Singapore : Springer Singapore. - 2196-2812 .- 0933-033X. ; 285, s. 97-123
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Book chapter (other academic/artistic)abstract
- Phosphorus and nitrogen containing dilute bismides differ from arsenic and antimony containing bismides in that the anions have large differences in atomic size and electronegativity, offering rich potentials for strain as well as bandgap engineering. In this chapter, we show theoretical modeling, epitaxy and characterizations of III-PBi and III-NBi and their quaternary alloys.
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