| 1. |
- Wang, Shu Min, 1963, et al.
(author)
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Progress on III-V-Bi Alloys and Light Emitting Devices
- 2018
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In: International Conference on Transparent Optical Networks. - 2162-7339. ; 2018-July
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Conference paper (peer-reviewed)abstract
- In this invited talk, we will present some recent progresses on epitaxial growth of III-V-Bi alloys and light emitting devices. Aluminum containing bismides including AlAsBi and AlSbBi have been epitaxially grown for the first time and their physical properties will be reported. New designs of using delta-doping in quantum wells are investigated to effectively extend light emission wavelength. Finally, GaAs based light emitting diode will be presented.
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| 2. |
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| 3. |
- Chen, Q, et al.
(author)
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Photoluminescence from tensile-strained Ge quantum dots
- 2016
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In: The 2016 IEEE Summer Topical Meeting Series, SUM 2016, Newport Beach, USA, July 11th-13th, 2016. - 9781509019007 ; , s. 120-121
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Conference paper (peer-reviewed)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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| 4. |
- Wang, P., et al.
(author)
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Influence of GaAsBi Matrix on Optical and Structural Properties of InAs Quantum Dots
- 2016
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In: Nanoscale Research Letters. - : Springer Science and Business Media LLC. - 1556-276X .- 1931-7573. ; 11:1
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Journal article (peer-reviewed)abstract
- InAs/GaAsBi dot-in-well structures were fabricated using gas-source molecular beam epitaxy and investigated for its optical and structural properties. GaAsBi-strained buffer layer and strain reduction layer are both effective to extend the photoluminescence (PL) emission wavelength of InAs quantum dot (QD). In addition, a remarkable PL intensity enhancement is also obtained compared with low-temperature-grown GaAs-capped InAs QD sample. The GaAsBi matrix also preserves the shape of InAs QDs and leads to increase the activation energy for nonradiative recombination process at low temperature. Lower density and larger size of InAs QDs are obtained on the GaAsBi surface compared with the QDs grown on GaAs surface.
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| 5. |
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| 6. |
- Chen, Q., et al.
(author)
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Tuning the Optoelectronic Properties of Capped Tensile-strained Ge Quantum Dots by Lattice Mismatch
- 2018
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In: Cailiao Daobao/Materials Review. - 1005-023X. ; 32:3, s. 1004-1009
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Journal article (peer-reviewed)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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| 7. |
- Han, Y., et al.
(author)
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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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In: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 33:8
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Journal article (peer-reviewed)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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| 8. |
- Han, Y., et al.
(author)
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Suspended GeSn microstructure for light source on Si
- 2017
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In: 2017 IEEE Photonics Society Summer Topicals Meeting Series, SUM 2017, San Juan, Puerto Rico, 10-12 July 2017. - 9781509065707 ; , s. 69-70
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Conference paper (peer-reviewed)abstract
- A novel suspended GeSn microstructure is demonstrated by selective etching of GeSn thin film on Ge. XRD and ?-Raman measurements show that the compressive strain in the GeSn thin film is effectively relaxed, and furthermore, unexpected tensile strain was introduced in the suspended GeSn.
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| 9. |
- Li, Y., et al.
(author)
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Novel group IV nano- and micro-structures for light sources on silicon
- 2017
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In: 2017 IEEE Photonics Society Summer Topicals Meeting Series, SUM 2017; San Juan Marriott ResortSan Juan; Puerto Rico; 10 July 2017 through 12 July 2017. - 9781509065707 ; , s. 43-44
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Conference paper (peer-reviewed)abstract
- We present our recent researches on novel group IV nano- and micro-structures for potential light sources on Si, including the tensile strained Ge quantum dots (QDs), GeSn thin films and microstructures, and Ge(Sn) nanowires. Tensile-strained Ge QDs were grown by SS-MBE, and photoluminescence was achieved. The GeSn thin films were demonstrated with Sn concentration above the bandgap transition critical point, and partially suspended GeSn microstructures were fabricated for relaxing the compressive strain.
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| 10. |
- Liu, J. J., et al.
(author)
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Bi2Te3 photoconductive detectors on Si
- 2017
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 110:14
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Journal article (peer-reviewed)abstract
- The peculiar properties of the gapless surface states with a Dirac cone shaped energy dispersion in topological insulators (TIs) enable promising applications in photodetection with an ultra-broad band and polarization sensitivity. Since many TIs can be easily grown on silicon (Si) substrates, TIs on Si could make an alternative route for photon detection of Si photonics. We present good device performances of a Si-based single-crystal bismuth telluride (Bi2Te3) photoconductive detector. Room temperature photo responses to 1064 nm and 1550 nm light illumination were demonstrated. Linear dependences of the photocurrent on both the incident light power and the bias voltage were observed. The main device parameters including responsivity and quantum efficiency were extracted. Published by AIP Publishing.
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