| 1. |
- Pan, Wenwu, et al.
(author)
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Photoluminescence of InGaAs/GaAsBi/InGaAs type-II quantum wells grown by gas source molecular beam epitaxy
- 2017
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In: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 32:1
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Journal article (peer-reviewed)abstract
- InxGa1-xAs/GaAs1-yBiy/InxGa1-xAs (0.20 ≤x ≤0.22, 0.035 ≤y ≤0.045) quantum wells (QWs) were grown on GaAs substrates by gas source molecular beam epitaxy for realizing the type-II band edge line-up. Both type-I and type-II transitions were observed in the Bi containing W QWs and the photoluminescence intensity was enhanced in the sample with a high Bi content, which is mainly due to the improvement of carrier confinement. The 8 band k • p model was used to analyze the electronic properties in the QWs and the calculated transition energies fit well with the experiment results. Our study shows that the proposed type-II QW is a promising candidate for realizing GaAs-based near infrared light emitting devices near 1.3 μm
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| 2. |
- Pan, W. W., et al.
(author)
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Raman scattering studies of dilute InP1-xBix alloys reveal unusually strong oscillator strength for Bi-induced modes
- 2015
-
In: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 30:9
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Journal article (peer-reviewed)abstract
- Room-temperature Raman scattering studies of new InP1-xBix alloys grown by molecular beam epitaxy are reported. Two new Bi-induced vibrations observed at 149 and 171 cm-1 are assigned to InBi-like TO and LO phonon modes, respectively, and exhibit an unusually strong intensity for the dilute regime. Two additional modes at 311 and 337 cm-1 are resolved as well with unknown origins. The Raman intensities of the InBi-like TO and LO bands, as well as the new mode at 337 cm-1, exhibit strong and linear dependence on the Bi concentration for the composition range studied, 0.003 ≤ x ≤ 0.023. This correlation may serve as a fast and convenient means of characterizing bismuth composition not only in the ternary alloy InP1-xBix but also in the quaternaries such as In1-yGayP1-xBix and In1-yAlyP1-xBix.
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| 3. |
- Wu, X. Y., et al.
(author)
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Effect of rapid thermal annealing on InP1-xBix grown by molecular beam epitaxy
- 2015
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In: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 30:9
-
Journal article (peer-reviewed)abstract
- The effect of post-growth rapid thermal annealing on structural and optical properties of InP1-xBix thin films was investigated. InPBi shows good thermal stability up to 500 °C and a modest improvement in photoluminescence (PL) intensity with an unchanged PL spectral feature. Bismuth outdiffusion from InPBi and strain relaxation are observed at about 600 °C. The InPBi sample annealed at 800 °C shows an unexpected PL spectrum with different energy transitions.
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| 4. |
- Chen, Xiren, et al.
(author)
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Bi-Induced Electron Concentration Enhancement Being Responsible for Photoluminescence Blueshift and Broadening in InAs Films
- 2019
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In: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 256:5
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Journal article (peer-reviewed)abstract
- Photoluminescence (PL) study is conducted on InAs films molecular beam epitaxially grown on GaAs substrates with different Bi flux levels. A PL peak blueshift accompanied by linewidth broadening is found with the increase of Bi/As flux ratio, in contrast to the common Bi isoelectronic incorporation or surfactant effect. It is, with detailed lineshape analysis and the evidence of PL peak splitting in a magnetic filed, attributed to the electron concentration enhancement induced by Bi flux. The electron concentration in InAs film is evaluated, which is about 5-fold enhanced as Bi/As flux ratio rises up from 0 to 1x10(-3). The temperature dependence of the PL spectrum indicates that the carrier redistribution augments while the carrier-phonon Frohlich scattering weakens in InAs films with high Bi/As flux ratios. These findings reveal a novel Bi effect of electron concentration enhancement, and contribute to the basic knowledge of Bi in III-V semiconductors.
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| 5. |
- Han, Y., et al.
(author)
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Critical Thickness and Radius for Axial Heterostructure Nanowires Using Finite Element Method
- 2009
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In: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 9:5, s. 1921-1925
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Journal article (peer-reviewed)abstract
- Finite-element methods are used to simulate a heterostructured nanowire grown on a compliant mesa substrate. The critical thickness is calculated based on the overall energy balance approach. The strain field created by the first pair of misfit dislocations, which offsets the initial coherent strain field, is simulated. The local residual strain is used to calculate the total residual strain energy. The three-dimensional model shows that there exists a radius-dependent critical thickness below which no misfit dislocations could be generated. Moreover, this critical thickness becomes infinity for a radius less than some critical values. The simulated results are in good agreement with the experimental data. The critical radius from this work is smaller than that obtained from previous models that omit the interaction between the initial coherent strain field and the dislocation-induced strain field.
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| 6. |
- Liu, Juanjuan, et al.
(author)
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Electrically injected GaAsBi/GaAs single quantum well laser diodes
- 2017
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In: AIP Advances. - : AIP Publishing. - 2158-3226 .- 2158-3226. ; 7:11, s. Article Number: 115006 -
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Journal article (peer-reviewed)abstract
- We present electrically injected GaAs/GaAsBi single quantum well laser diodes (LDs) emitting at a record long wavelength of 1141 nm at room temperature grown by molecular beam epitaxy. The LDs have excellent device performances with internal quantum efficiency of 86%, internal loss of 10 cm-1 and transparency current density of 196 A/cm2. The LDs can operate under continuous-wave mode up to 273 K. The characteristic temperature are extracted to be 125 K in the temperature range of 77?150 K, and reduced to 90 K in the range of 150?273 K. The temperature coefficient of 0.3 nm/K is extracted in the temperature range of 77?273 K.
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| 7. |
- Song, Yuxin, 1981, et al.
(author)
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Growth of GaSb1-xBix by molecular beam epitaxy
- 2012
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In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures. - : American Vacuum Society. - 2166-2754 .- 2166-2746. ; 30:2, s. 02B114-
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Journal article (peer-reviewed)abstract
- Molecular beam epitaxy for GaSb1-xBix is investigated in this article. The growth window for incorporation of Bi in GaSb was found. Strategies of avoiding formation of Bi droplets and enhancing Bi incorporation were studied. The Bi incorporation was confirmed by SIMS and RBS measurements. The Bi concentration in the samples was found to increase with increasing growth temperature and Bi flux. The position of GaSb1-xBix layer peak in XRD rocking curves is found to be correlated to Bi composition. Surface and structural properties of the samples were also investigated. Samples grown on GaSb and GaAs substrates were compared and no apparent difference for Bi incorporation was found.
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| 8. |
- Song, Yuxin, 1981, et al.
(author)
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Molecular beam epitaxy growth of InSb1-xBix thin films
- 2013
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In: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248 .- 1873-5002. ; 378, s. 323-328
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Journal article (peer-reviewed)abstract
- Molecular beam epitaxy growth for InSb1-xBix thin films on (100) GaAs substrates is reported. Successful Bi incorporation for 2% is achieved, and up to 70% of the incorporated Bi atoms are at substitutional sites. The effects of growth parameters on Bi incorporation and surface morphology are studied. Strong In and Ga inter-diffusion induced by Bi incorporation is observed and discussed.
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| 9. |
- Wang, Shu Min, 1963, et al.
(author)
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Novel Dilute Bismides for IR Optoelectronics Applications
- 2013
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In: Asia Communications and Photonics Conference, ACP. - Washington, D.C. : OSA. - 2162-108X.
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Conference paper (peer-reviewed)abstract
- III-V-Bi compounds reveal a number of attractive physical properties promising for novel IR optoelectronic applications [1,2] and have received considerable attention as witnessed by the dedicated international workshops on this topic in the consecutive past four years. The isoelectronic nature of Bi atoms in III-Vs induces strong interactions with the energy bands of host materials leading to large band-gap reduction, less temperature sensitive band-gap and large spin-orbit split band. So far the most studied material is Ga(N)AsBi, while other dilute bismides have also been reported recently. In this paper, we shall briefly review several novel bismides: GaSbBi, InSbiBi, InAsBi, InPBi and InGaAsBi, and the Bi surfactant effect from our group, all grown by molecular beam epitaxy (MBE).
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| 10. |
- Charpentier, Sophie, 1983, et al.
(author)
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Induced unconventional superconductivity on the surface states of Bi2Te3 topological insulator
- 2017
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 8:1
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Journal article (peer-reviewed)abstract
- Topological superconductivity is central to a variety of novel phenomena involving the interplay between topologically ordered phases and broken-symmetry states. The key ingredient is an unconventional order parameter, with an orbital component containing a chiral p(x) + ip(y) wave term. Here we present phase-sensitive measurements, based on the quantum interference in nanoscale Josephson junctions, realized by using Bi2Te3 topological insulator. We demonstrate that the induced superconductivity is unconventional and consistent with a sign-changing order parameter, such as a chiral px + ipy component. The magnetic field pattern of the junctions shows a dip at zero externally applied magnetic field, which is an incontrovertible signature of the simultaneous existence of 0 and pi coupling within the junction, inherent to a non trivial order parameter phase. The nano-textured morphology of the Bi2Te3 flakes, and the dramatic role played by thermal strain are the surprising key factors for the display of an unconventional induced order parameter.
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