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| 2. |
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| 3. |
- Yue, L., et al.
(författare)
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Novel InGaPBi single crystal grown by molecular beam epitaxy
- 2015
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Ingår i: Applied Physics Express. - : IOP Publishing. - 1882-0786 .- 1882-0778. ; 8:4, s. Art. no. 041201-
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Tidskriftsartikel (refereegranskat)abstract
- InGaPBi crystalline thin films with up to 2.1% bismuth concentration have been grown on GaAs substrates by molecular beam epitaxy. Rutherford backscattering spectrometry confirms that the majority of Bi atoms are located at substitutional lattice sites. The films exhibit good surface, structural, and interface quality, and their strains can be tuned from tensile to compressive by increasing the Bi content. InBi LO and GaBi LO vibrational modes in Raman spectroscopy were observed, and their intensities increased with Bi concentration. A weak photoluminescence signal was observed at 1.78 eV at room temperature for the sample with a Bi content of 0.5%.
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| 4. |
- Chen, Q. M., et al.
(författare)
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A new route toward light emission from Ge: tensile-strained quantum dots
- 2015
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 7:19, s. 8725-8730
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Tidskriftsartikel (refereegranskat)abstract
- The tensile-strained Ge quantum dot (QD) is proposed as a new route for the realization of direct band gap conversion in Ge. Ge QDs were successfully grown on an InP substrate by molecular beam epitaxy. The strain field in the QDs were analyzed by high resolution transmission electron microscopy and simulated by the finite element method based on the measured geometries. The strain field in the QDs is found to be non-uniform and the shear component plays a significant role in the energy band structure, leading to larger required hydrostatic strain than that in the Ge thin films under biaxial strain to become a direct band gap.
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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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| 8. |
- Zhao, Shuyan, et al.
(författare)
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Stress and strain analysis of Si-based III - V template fabricated by ion-slicing
- 2020
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Ingår i: Chinese Physics B. - : IOP Publishing. - 1674-1056. ; 29:7
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Tidskriftsartikel (refereegranskat)abstract
- Strain and stress were simulated using finite element method (FEM) for three III-V-on-Insulator (III-VOI) structures, i.e., InP/SiO2/Si, InP/Al2O3/SiO2/Si, and GaAs/Al2O3/SiO2/Si, fabricated by ion-slicing as the substrates for optoelectronic devices on Si. The thermal strain/stress imposes no risk for optoelectronic structures grown on InPOI at a normal growth temperature using molecular beam epitaxy. Structures grown on GaAsOI are more dangerous than those on InPOI due to a limited critical thickness. The intermedia Al2O3 layer was intended to increase the adherence while it brings in the largest risk. The simulated results reveal thermal stress on Al2O3 over 1 GPa, which is much higher than its critical stress for interfacial fracture. InPOI without an Al2O3 layer is more suitable as the substrate for optoelectronic integration on Si.
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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, 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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