Studies on strained and strain-compensated GaAsSb-related quantum well structures
Date Issued
2006
Date
2006
Author(s)
Wan, Cheng-Tien
DOI
zh-TW
Abstract
In this thesis, we report the optical properties of strained and strain- compensated GaAsSb-based quantum well (QW) structures. First, we investigated the effects of barrier thickness on the gain spectrum of GaAsSb/GaAs QW. For a QW with a well thickness of 7 nm and a carrier density of 4x1012 cm-2, the material gain can be enhanced from 400 to 600 cm-1 as the GaAs barrier thickness is decreased from 80 to 5 nm. The reduction in barrier thickness can decrease the threshold carrier density by 50% with a constrained blue-shift in peak wavelength. Second, we investigated GaAsP/GaAs/GaAsSb strain-compensated QW structure. The introduction of tensile-strained GaAsP in GaAsSb/GaAs system can compensate the compressive strain resulted from GaAsSb and makes multiple quantum well (MQW) structure possible. Our simulation results show that MQW structure has larger threshold carrier density, higher differential gain and less blue shift in peak wavelength as compared with single QW structure. Preliminary experimental study reveals that the strain-compensated MQW structure has narrower photoluminescence linewidth than the ordinary MQW structure, indicating the better interface properties due to strain compensation. Third, we studied InGaAsSb/GaAs QWs. Incorporating indium into GaAsSb can reduce the conduction band offset between the GaAsSb and GaAs and enhance the wavefunction overlap of electron and hole. However, it also results in blue shift in gain peak. A trade-off between gain and blue-shift is considered. As the indium composition is 0.02, the threshold carrier density can be reduced by 12% while the emitting at 1300 nm is sustained.
Subjects
砷銻化鎵
量子井
模擬
GaAsSb
quantum well
simulation
Type
thesis
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