Improving the performance of strained InGaAs/AlGaAs single quantum well lasers
作者:
D. P. Bour,
Ramon U. Martinelli,
F. Z. Hawrylo,
G. A. Evans,
N. W. Carlson,
D. B. Gilbert,
期刊:
Applied Physics Letters
(AIP Available online 1990)
卷期:
Volume 56,
issue 4
页码: 318-320
ISSN:0003-6951
年代: 1990
DOI:10.1063/1.102815
出版商: AIP
数据来源: AIP
摘要:
By adjusting the carrier confining structure and the optical confining structure of strained InGaAs/AlGaAs single quantum well (QW) lasers, an improvement in performance has been obtained. First, the influence of optical confinement was examined by comparing two graded‐index confining structures. For InxGa1−xAs QWs with eitherx=0.20 orx=0.25, lasers with greater optical confinement factor had improved performance, with both lower threshold (180 A/cm2forx=0.20) and higher characteristic temperature (250 K forx=0.20), despite their reduced carrier confining potentials. Second, experiments on graded‐composition quantum wells show that thin step‐grading layers result in improved performance. In this structure, where the QW hasx=0.35, and the step layers havex=0.15, the optimum step thickness is 30–40 A˚. Thicker step layers appear to create too much strain, degrading the laser operation. These results indicate that step grading of strained QWs produces active region interfaces with lower defect density, and that step grading is especially useful in improving the performance of long‐wavelength, highly strained InGaAs/AlGaAs QW lasers.
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