GaAs長波長雷射元件材料之退火處理

• Main Authors: Chia-hua Chen, 陳家驊
• Other Authors: Chun-Hao Koo
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/25077679304781183663

碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 89 === Traditional 1.3 and 1.55m edge emitting laser diodes based on InP material system are currently used in telecommunication systems for long distance network. The price of the transmitting unit of such kind of laser is so high that limit the application of these optical communication systems in local area network (datacom). The alternative approach for communication light sources relies on the concept of vertical cavity surface emitting laser (VCSEL). These lasers offer simple coupling with fibre because of circle output beam. In this way it is possible to dramatically reduce the price for transmitting unit. The main challenge for creation of VCSELs based on traditional InP material system including : insufficient variation in band gap, poor quality DBR, and poor thermal conductivity. The GaAs-based material system may overcome all the problems mentioned above. There are two main approaches in this research : by using InAs/InGaAs quantum dot or by using InGaNAs quantum well monolithically grown on GaAs. The present work is to apply to approaches and to develop post-growth annealing method for improving optical properties of material structures mentioned above. The heat treatments were carried out at high temperature for a short period of time to simulate the influence of rapid thermal annealing on samples. It was expected that the effects of composition and annealing parameters on the wavelength shift and optical intensity could be measured by the photoluminescence method and the optimized process could be found. After thermal annealing, SEM-EDX and atomic force microscope (AFM) were used to analyze surface microstructure of the samples. Experimental results indicate that annealing above 560oC will cause a signifucant blue shift in PL spectra on InAs/InGaAs quantum dot samples, and PL intensity of InGaNAs/GaAs was enhanced about 70 times by thermal annealing at the annealing condition of 750oC for 1 hour. Besides, the surface of wafer is still mirror-like after annealing, which is a suitable annealing process to keep good surface condition. These results should be helpful in the development of new long-wavelength laser devices.