Development of InGaAs/GaAs strained single quantum well laser by phase looked epitaxy method.

1992 Fiscal Year Final Research Report Summary

• Project/Area Number: 03452258
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: 金属材料(含表面処理・腐食防食)
• Research Institution: Osaka University
• Principal Investigator: YOSHII Kumayasu Department of Presision Eng. Osak univ. prof., 工学部, 教授 (30029152)
• Co-Investigator(Kenkyū-buntansha): KAKIUCHI Hiroaki Department of Presision Eng. Osak assistant, 工学部, 助手 (10233660) ; YASUTAKE Kiyoshi Department of Presision Eng. Osak asso. prof., 工学部, 助教授 (80166503) ; KAWABE Hideaki Department of Presision Eng. Osak univ. prof., 工学部, 教授 (90028978)
• Project Period (FY): 1991 – 1992
• Keywords: semiconductor laser / phase locked epitaxy / strained quantum well / photoluminescence

Research Abstract

The crystallinity and optical property of InGaAs/GaAs strained single quantum well(SSQW) structure were studied by photoluminescence (PL) method in relation to the crystal growth conditions. A PL spectrum of InGaAs/GaAs SSQW structure made by MBE at 540ﾟC showed a peak shift of the QW luminescence line toward the lower wave length than the theoretically estimated position. This fact suggests that In atoms evaporate during MBE growth of InGaAs layer, resulting in the decrease of chi in In_<chi>Ga_<1-chi>As active layer. Because the In evaporation is thermally enhanced process, it is considered that lowering the deposition temperature is effective to suppress the In evaporation.
In order to reduce the growth temperature of the InGaAs layer, we grow the InGaAs layer by applying MEE method, which.is known as a effective technique to reduce the growth temperature of AlGaAs/GaAs alloy semiconductor system. The PL spectra of the SSQW structure grown by MEE method showed that the In evaporation could be controlled by decreasing the growth temperature to 290ﾟC. However, FWHM of the PL line became broader than the one from the SSQW structure made by MBE at 540ﾟC. Also the RHEED pattern showed that the crystal quality of the film made at low temperature is inferior to the high temperature grown film.
The excess As adhesion and the low mobility of the group III atoms were believed to be the key factors to determine the crystal quality of the SSQW structure grown at low temperatures. So we optimized the low temperature MEE growth condition by increasing the migration time of the group III atoms and by reducing the As partial pressure. The SSQW structure made by the optimized low temperature MEE process showed the comparable qualities in optical and crystallographic properties to the films made by the high temperature MBE process.
It is demonstrated that the highly controlled InGaAs/GaAs SSQW structure in composition, crystallinity and optical quality were made by the optimized low temperature MEE process, which may be the promising process to obtain the SSQW laser devices.