| 1. |
- Wu, Xiaoyan, et al.
(författare)
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Anomalous photoluminescence in InP1-xBix
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 6, s. Art. no. 27867-
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Tidskriftsartikel (refereegranskat)abstract
- Low temperature photoluminescence (PL) from InP1-xBix thin films with Bi concentrations in the 0-2.49% range reveals anomalous spectral features with strong and very broad (linewidth of 700 nm) PL signals compared to other bismide alloys. Multiple transitions are observed and their energy levels are found much smaller than the band-gap measured from absorption measurements. These transitions are related to deep levels confirmed by deep level transient spectroscopy, which effectively trap free holes and enhance radiative recombination. The broad luminescence feature is beneficial for making super-luminescence diodes, which can theoretically enhance spatial resolution beyond 1 ?m in optical coherent tomography (OCT).
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| 2. |
- 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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| 3. |
- Liu, Juanjuan, et al.
(författare)
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Electrically injected GaAsBi/GaAs single quantum well laser diodes
- 2017
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226 .- 2158-3226. ; 7:11, s. Article Number: 115006 -
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Wang, L, et al.
(författare)
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Influence of Bi on morphology and optical properties of InAs QDs
- 2017
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Ingår i: Optical Materials Express. - 2159-3930. ; 7:12, s. 4249-4257
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Tidskriftsartikel (refereegranskat)abstract
- We study the tsurface morphology and photoluminescence (PL) property of InAs quantum dots (QDs) on GaAs using bismuth (Bi) in the layer prior to or after the growth of QDs. Incorporating Bi in the layer prior to the QD deposition delays the onset of InAs QD formation resulting in a decrease in QD height and density. As a surfactant, adding Bi in the GaAs capping layer at a high growth temperature reduces the In surface diffusion length leading to uniform and well preserved InAs QDs in terms of height and density. The incorporation of 3% Bi at a low growth temperature, which forms a GaAsBi capping layer, can effectively lower the PL transition energy up to 163 meV and reduce the PL linewidth, leading to an emission wavelength of 1.365 ?m at 77 K.
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| 5. |
- Wang, L, et al.
(författare)
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Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application
- 2017
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Ingår i: Crystals. - : MDPI AG. - 2073-4352. ; 7:3, s. Article no 63 -
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Forskningsöversikt (refereegranskat)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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| 6. |
- Wang, Shu Min, 1963, et al.
(författare)
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Novel Dilute Bismides for IR Optoelectronics Applications
- 2013
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Ingår i: Asia Communications and Photonics Conference, ACP. - Washington, D.C. : OSA. - 2162-108X.
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Konferensbidrag (refereegranskat)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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| 7. |
- Yan, Bing, et al.
(författare)
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Bismuth-induced band-tail states in GaAsBi probed by photoluminescence
- 2019
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 114:5
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Tidskriftsartikel (refereegranskat)abstract
- Band-tail states in semiconductors reflect the effects of material growth and/or treatment, affect the performance of optoelectronic applications, and are hence a well-concerned issue. Dilute-Bi GaAs is considered very competitive though the role of Bi is yet to be well clarified. We in this letter investigate the effect of Bi incorporation on the band-tail states in GaAs 1−x Bi x by excitation power- and magnetic field-dependent photoluminescence (PL) measurements at low temperatures. Three PL features are identified from a broad PL peak, which blue-shift monotonically with the increase in excitation power. None of the PL features correlate with single Bi-content free-exciton recombination, and band-tail filling rather than the donor-acceptor pair process is responsible for the power-induced blueshift. The density of band-tail states gets enhanced with the increase in the Bi incorporation level and affects the determination of Bi-induced bandgap reduction. The results indicate that joint analysis of excitation- and magneto-PL may serve as a good probe for band-tail states in semiconductors.
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| 8. |
- Yue, L., et al.
(författare)
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Molecular beam epitaxy growth and optical properties of high bismuth content GaSb1-xBix thin films
- 2018
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 742, s. 780-789
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Tidskriftsartikel (refereegranskat)abstract
- Epitaxial growth of GaSb 1–x Bi x thin films on GaSb (100) substrates were studied by varying V/III ratio, growth temperatures and Bi flux using molecular beam epitaxy. It is demonstrated that reducing the V/III ratio facilitates Bi incorporation into GaSb effectively. The highest average Bi content up to 11% with locally up to 13% is achieved, confirmed by Rutherford backscattering spectroscopy and transmission electron microscopy (TEM). X-ray diffraction and TEM show perfect crystal quality for the GaSb 1–x Bi x film with x = 5.6%. The composition dependence room temperature photoluminescence (PL) spectra of the GaSb 1–x Bi x alloys with 0 < x ≤ 13% are reported for the first time. The band-gap energy decreases effectively with increasing the Bi content and in the range of 1 ≤ x ≤ 5.6%, the linear decreasing rate is 37 meV/Bi%. For the highest Bi content GaSb 1–x Bi x , the PL peak energy reaches 0.41 eV (3.0 μm), indicating that GaSb 1–x Bi x alloy has potentials in mid-infrared optoelectronic applications.
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| 9. |
- 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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| 10. |
- Chen, X, et al.
(författare)
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Bismuth Effects on Electronic Levels in GaSb(Bi)/AlGaSb Quantum Wells Probed by Infrared Photoreflectance
- 2015
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Ingår i: Chinese Physics Letters. - 0256-307X .- 1741-3540. ; 32:6
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Tidskriftsartikel (refereegranskat)abstract
- GaSb(Bi)/Al0.2Ga0.8Sb single quantum wells are characterized by a Fourier transform infrared spectrometerbased photoreflectance method at 77 K. Spatially direct and indirect transitions between the electronic levels at and above the effective band gap are well resolved. The shifts of the electronic levels with Bi incorporation are identified quantitatively. The results show that the upshift of the valence band edge is clarified to be dominant, while the Bi-induced downshift of the conduction band edge does exist and contributes to the band gap reduction in the GaSbBi quantum-well layer by (29±6)%.
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