| 1. |
- Pan, W. W., et al.
(författare)
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Raman scattering studies of dilute InP1-xBix alloys reveal unusually strong oscillator strength for Bi-induced modes
- 2015
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 30:9
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Wu, X. Y., et al.
(författare)
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Effect of rapid thermal annealing on InP1-xBix grown by molecular beam epitaxy
- 2015
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 30:9
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Tidskriftsartikel (refereegranskat)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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| 3. |
- Yan, J. Y., et al.
(författare)
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Wavelength tuning of InAs quantum dot laser by micromirror device
- 2015
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 425, s. 373-375
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Tidskriftsartikel (refereegranskat)abstract
- We report on the InAs quantum dot (QD) external cavity laser (ECL) using a digital mirror device (DMD) as the key component for wavelength tuning. The InAs QD laser diode was grown by gas source molecular-beam epitaxy, which had a broad gain profile. Single mode operation was achieved with the side mode suppression ratio of 21 dB when the optical feedback was provided by a mirror pattern consisting of 9 micromirrors. Moreover, two-color lasing was demonstrated with two laser lines having frequency difference in the THz range. The incorporation of DMD in the ECL enables great flexibility and many unique features, such as high tuning speed independent of the tuning step, two-color or multicolor lasing, and adjustable intensity for individual laser lines. (C) 2015 Elsevier B.V. All rights reserved.
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| 4. |
- Song, Yuxin, 1981, et al.
(författare)
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Natural patterning of templates on GaAs by formation of cracks
- 2015
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226 .- 2158-3226. ; 5:6, s. Art Nr 067146-
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Tidskriftsartikel (refereegranskat)abstract
- Substrate pre-patterning is an effective way to overcome large lattice mismatch and suppress threading defects in the growth of heterostructures. In this work, a new concept was proposed to form natural patterns on commercial substrates monolithically by the formation of surface cracks. Tensile strain was intentionally brought in with a GaAs or GaNAs layer above an InGaAs layer on GaAs substrates. Surface crack patterns successfully formed during the strain relaxation. The strain in a 1 μm buffer layer atop the pattern was found effectively relaxed. Detailed residual strain distribution was simulated by the finite element method.
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| 5. |
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| 6. |
- Song, Y. X., et al.
(författare)
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Evolution of Bi2Te3 on GaN Grown by MBE
- 2014
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Ingår i: The 18th International Conference on Molecular Beam Epitaxy, Flagstaff, USA, September 7-12, 2014.
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Konferensbidrag (refereegranskat)
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| 7. |
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| 8. |
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| 9. |
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| 10. |
- Xu, H., et al.
(författare)
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Raman spectroscopy of epitaxial topological insulator Bi2Te3 thin films on GaN substrates
- 2015
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Ingår i: Modern Physics Letters B. - : World Scientific Pub Co Pte Lt. - 0217-9849 .- 1793-6640. ; 29:15
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Tidskriftsartikel (refereegranskat)abstract
- Bi2Te3 has drawn great attention in recent years as both a topological insulator and the best thermoelectric material at room temperature. We report on Raman spectroscopic study on Bi2Te3 thin films with thicknesses of 20-50 nm grown on GaN by molecular beam epitaxy. All the four classical optical phonon modes are clearly revealed for the first time in ex situ Raman for epitaxial Bi2Te3. Unusual and infrared-active vibration modes are also observed and analyzed. In the resonant Raman measurements, abnormal enhancement and suppression of different modes are studied. The interface modes caused by a large density of domain boundaries formed during coalescence of crystal islands with different lattice orientations and the Frohlich electron-phonon interaction are found to play significant roles during the Raman scattering processes.
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