The Study on the Band Alignment and Characterization of GaAsSb/GaAs Quantum Well Lasers
Date Issued
2005
Date
2005
Author(s)
Tsai, Chung-Lin
DOI
zh-TW
Abstract
In the past decade, many research groups reported their valence band offset ratio (Qv0) for GaAsSb/GaAs system, but no common consensus is made yet. In this study, we propose a novel method to determine the valence band offset ratio by comparing the wavelength- cavity length relation of a GaAs0.64Sb0.36/GaAs single quantum well laser with a self-consistent solution. The determined valence band offset ratio and bowing parameter are Qv0 = 1.02 and bg = -1.31 eV respectively. In this calculation, we also found that when the carrier density is low, the dominant transition is from electron excited state to hole ground state. Only when the carrier density is high enough to form the band bending, electron ground state becomes the dominant transition level. Simulation results also show that spontaneous recombination does not dominate the characteristic temperature of our laser. A new quantum well structure with narrow GaAs barrier is analyzed. The simulation shows that the structure can enhance the coupling between electron and heavy hole wavefunctions. It may reduce the threshold current density, and further, improve the characteristic temperature, as long as the strain can be accommodated by the lattice.
Subjects
銻砷化鎵
砷化鎵
第二型量子井
光通訊
雷射
GaAsSb
GaAs
Type- II
Quantum well
Laser
optical communication
Type
thesis
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