| 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. |
- Wang, Chang, et al.
(författare)
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Molecular beam epitaxy growth of AlAs 1-x Bi x
- 2019
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 34:3
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Tidskriftsartikel (refereegranskat)abstract
- High quality AlAs 1-x Bi x layers with Bi composition of 3%-10.5% have been successfully grown by molecular beam epitaxy. The Bi incorporation is confirmed by Rutherford backscattering spectroscopy. For a 400 nm thick AlAsBi layer, the strain relaxation occurs when the Bi composition is larger than 6.5%. Flux ratio is calculated from Knudsen-cell model and Maxwell equation, according to the geometrical relationship of our equipment. The Bi incorporation increases with increasing the As-Al flux ratio as well as the Bi flux. The extrapolation lattice constant of hypothetic zincblende AlBi alloy is about 6.23 Å.
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| 3. |
- 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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| 4. |
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| 5. |
- Zhang, L, et al.
(författare)
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Nanoscale Distribution of Bismuth in InPBi
- 2015
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Ingår i: 6th International Workshop on Bismuth Containing Semiconductors, Madison, USA, July 19th-22nd, 2015.
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Konferensbidrag (refereegranskat)
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| 6. |
- Chen, Q, et al.
(författare)
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Photoluminescence from tensile-strained Ge quantum dots
- 2016
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Ingår i: The 2016 IEEE Summer Topical Meeting Series, SUM 2016, Newport Beach, USA, July 11th-13th, 2016. - 9781509019007 ; , s. 120-121
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Konferensbidrag (refereegranskat)abstract
- It has been theoretically predicted that 1.9% biaxial tensile strain can convert Ge [1], which is compatible with Si CMOS technology, into a direct band-gap semiconductor, making it a candidate material for light sources on Si [2, 3]. Combining the advantage of tensile strain with quantum dot (QD), we proposed that tensile-strained QD is a new route toward light emission from Ge [4]. In this work, we chose In0.52Al0.48As, which is lattice matched to InP, as barrier layer and grew the structure by molecular beam epitaxy (MBE). Photoluminescence (PL) was successfully achieved at room temperature.
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| 7. |
- Chen, Q., et al.
(författare)
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Highly Tensile-Strained Self-Assembled Ge Quantum Dots on InP Substrates for Integrated Light Sources
- 2021
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 4:1, s. 897-906
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Tidskriftsartikel (refereegranskat)abstract
- Highly tensile-strained Ge quantum dots (TS-Ge-QDs) emitting structures with different size were successfully grown on InP substrates by molecular beam epitaxy. Dislocation-free TS-Ge-QDs were observed by transmission electron microscopy. Finite element modeling indicates a maximum tensile strain of 4.5% in the Ge QDs, which is much larger than the required strain to achieve direct band gap conversion of Ge based on theoretical prediction. Photoluminescence (PL) from a direct band-gap-like transition of TS-Ge-QDs with a peak energy of 0.796 eV was achieved and confirmed by the etch depth-dependent PL, temperature-dependent PL, and excitation-power-dependent PL. In addition, a strong defect-related peak of 1 eV was observed at room temperature. The band structure of the TS-Ge-QDs emitting structures was calculated to support the experimental results of PL spectra. Achieving PL from direct band-gap-like transitions of TS-Ge-QDs provides encouraging evidence of this promising highly tensile strained semiconductor-nanostructure-based platform for future photonics applications such as integrated light sources.
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| 8. |
- Chen, Q., et al.
(författare)
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Tuning the Optoelectronic Properties of Capped Tensile-strained Ge Quantum Dots by Lattice Mismatch
- 2018
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Ingår i: Cailiao Daobao/Materials Review. - 1005-023X. ; 32:3, s. 1004-1009
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Tidskriftsartikel (refereegranskat)abstract
- The optoelectronic properties of capped tensile-strained Ge quantum dot (QD) was studied with different lattice mismatch, which was formed by Ge and various substrate. The strain distribution of Ge QDs were simulated with the aid of finite element method (FEM) and the electronic structures of capped tensile-strained Ge QDs under such strain was calculated via deformation potential theory and effective mass approach (EMA). The size effect of Ge QDs was also considered. It was found that the capped QDs hold larger strain than the uncapped ones. In addition, the energy difference between Γ and L conduction valley reduced with the increase of the QD size and the lattice mismatch, thus converting the Ge QDs into the direct band gap material. The energy of the direct band gap decreased with the increase of the QDs' size. This work shows that the tensile-strained Ge QD is a promising light emission material for future optoelectronic applications such as lasers on Si.
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| 9. |
- Chi, Chaodan, et al.
(författare)
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Molecular beam epitaxy growth of GaSb1-xBix without rotation
- 2019
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Ingår i: Vacuum. - : Elsevier BV. - 0042-207X. ; 168
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Tidskriftsartikel (refereegranskat)abstract
- GaSb1-xBix thin film was grown on a 2 inch GaSb substrate by molecular beam epitaxy (MBE) without substrate rotation. Bi composition is found to vary from 2.76% to 3.98% across the wafer. The distribution of Bi content is mainly determined by spatial non-uniformity of Sb/Ga flux ratio, while Bi flux has slightly influence. Ostwald ripening process is confirmed to be reason for bigger Bi droplets via Bi surface diffusion. With the increase of Sb/Ga flux ratio, Ostwald ripening process is suppressed. At high Bi flux, excess Ga atoms accumulate on surface and form droplets.
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| 10. |
- Han, Y., et al.
(författare)
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A comparative study of selective dry and wet etching of germanium-tin (Ge1-xSnx) on germanium
- 2018
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 33:8
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Tidskriftsartikel (refereegranskat)abstract
- A comparative study of selective dry and wet etching methods for germanium-tin (Ge1-xSnx) alloys (3.5% < x < 7.7%) and germanium (Ge) is carried out. Both etching methods are optimized from the perspectives of selectivity and morphology, and then compared. A special behavior of the selective dry etching process is discovered and explained, whereby the selectivity has a dramatic increase to as high as 336 when the Sn concentration is above 6%. Different morphologies of suspended microstructures fabricated by different etching methods are investigated. Comparative study shows that the selective dry etching is a better choice for high Sn concentration GeSn (above 7%) against Ge to have better morphology, selectivity and verticality. While for low Sn concentration GeSn (below 6%), wet etching is a better way to fabricate a suspended GeSn microstructure on Ge. This work provides a comparative understanding of both methods of selective etching for GeSn. This comparative understanding is expected to be applied in the processing of next generation electronic and photonic devices.
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