Type II heterostructures with InSb quantum dots inserted into p-n InAs(Sb,P) junction

摘要

We report on study of electrical and optical properties of type II heterostructures with InSb quantum dots (QDs) inserter into the InAs-based p-n junction made by LPE-MOVPE combine method. InSb QDs were grown on an InAs(100) substrate by LPE. Overgrowth on the surface with the self-assembled InSb QD arrays was performed by MOVPE using capping layers based on binary InAs and quaternary InAsSb solid solutions. High-resolution cross-sectional image of the InSb QDs buried into the InAs(Sb,P) matrix was obtained for the first time by transmission electron microscopy. Structural parameters of the InSb QDs such as size, shape and internal strain were demonstrated and discussed. The uniform small QDs with high density (>10~(10) cm~(-2)) with dimensions of 3 nm in height and 14 nm in diameter were found to be self-assembled and dislocation-free without any extended defects, whereas the low-density large QDs (10~8 cm~(-2)) with dimensions of 10 nm in height and 50 nm in diameter were relaxed and demonstrated interface strain with the InAs substrate. I-V characteristics of the mesa-diode heterostructures with the InSb QDs inserted into InAs p-n junction were studied at the wide temperature range T=77-300 K. Intense positive and negative electroluminescence for both n-InAs/pInAs and n-InAs/InSb-QDs/p-InAs heterostructures was found in the spectral range 3-4 μm. Evolution of the spectra in dependence on applied external bias (forward and reverse) were observed at 77 K and 300 K.