The photoluminescence spectrum （PL） of InAs quantum dots （QDs） at 80 K is studied by comparison between the theoretical calculation and experimental measurement. The Gaussian line shape is used to approximate the ...The photoluminescence spectrum （PL） of InAs quantum dots （QDs） at 80 K is studied by comparison between the theoretical calculation and experimental measurement. The Gaussian line shape is used to approximate the size distribution of QDs. Its mean volume and the standard full width at half maximum （FWHM） of the PL spectrum. size deviation are well correlated with the peak and The experimental PL spectrum is well reproduced by the theoretical model based on the effect mass approximation including the size distribution without any adjustable parameters. Compared with the standard size deviation value σ = 9 × 10^-2 determined by atomic force microscopic method a small value σ = 7 × 10^-2 is obtained by the best fitting process from the measured and calculated PL spectra.展开更多
Strained Hg Te thin films are typical three-dimensional topological insulator materials.Most works have focused on Hg Te(100)films due to the topological properties resulting from uniaxial strain.In this study,straine...Strained Hg Te thin films are typical three-dimensional topological insulator materials.Most works have focused on Hg Te(100)films due to the topological properties resulting from uniaxial strain.In this study,strained Hg Te(111)thin films are grown on Ga As(100)substrates with Cd Te(111)buffer layers using molecular beam epitaxy(MBE).The optimal growth conditions for Hg Te films are determined to be a growth temperature of 160℃and an Hg/Te flux ratio of 200.The strains of Hg Te films with different thicknesses are investigated by highresolution x-ray diffraction,including reciprocal space mapping measurements.The critical thickness of Hg Te(111)film on Cd Te/Ga As is estimated to be approximately 284 nm by Matthews'equations,consistent with the experimental results.Reflection high-energy electron diffraction and high-resolution transmission electron microscopy investigations indicate that high-quality Hg Te films are obtained.This exploration of the MBE growth of Hg Te(111)films provides valuable information for further studies of Hg Te-based topological insulators.展开更多
基金Supported by National Natural Science Foundation of China(92064014,11933006)Science and Technology Commission of Shanghai Municipality(18J1414900)Youth Innovation Promotion Association CAS。
基金the National Natural Science Foundation of China(60371040)and The Foundation of Science and Technology Commis-sion of Shanghai Municipality(03JC14076)
基金Supported by the National Natural Science Foundation of China under Grant No 10474020, the National Basic Research Programme of China under Grant No 2006CB13921507, and the Knowledge Innovation Project of Chinese Academy of Sciences.
文摘The photoluminescence spectrum （PL） of InAs quantum dots （QDs） at 80 K is studied by comparison between the theoretical calculation and experimental measurement. The Gaussian line shape is used to approximate the size distribution of QDs. Its mean volume and the standard full width at half maximum （FWHM） of the PL spectrum. size deviation are well correlated with the peak and The experimental PL spectrum is well reproduced by the theoretical model based on the effect mass approximation including the size distribution without any adjustable parameters. Compared with the standard size deviation value σ = 9 × 10^-2 determined by atomic force microscopic method a small value σ = 7 × 10^-2 is obtained by the best fitting process from the measured and calculated PL spectra.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11634009,61874069,1177041280 and 11574336)Shanghai Science and Technology Foundation(Grant No.18JC1420401)。
文摘Strained Hg Te thin films are typical three-dimensional topological insulator materials.Most works have focused on Hg Te(100)films due to the topological properties resulting from uniaxial strain.In this study,strained Hg Te(111)thin films are grown on Ga As(100)substrates with Cd Te(111)buffer layers using molecular beam epitaxy(MBE).The optimal growth conditions for Hg Te films are determined to be a growth temperature of 160℃and an Hg/Te flux ratio of 200.The strains of Hg Te films with different thicknesses are investigated by highresolution x-ray diffraction,including reciprocal space mapping measurements.The critical thickness of Hg Te(111)film on Cd Te/Ga As is estimated to be approximately 284 nm by Matthews'equations,consistent with the experimental results.Reflection high-energy electron diffraction and high-resolution transmission electron microscopy investigations indicate that high-quality Hg Te films are obtained.This exploration of the MBE growth of Hg Te(111)films provides valuable information for further studies of Hg Te-based topological insulators.
