Laser Induced Semiconductor Surface Grating Formation and Quantum Well Intermixing

• Main Authors: Cheng-yen Chen, 陳正言
• Other Authors: C. C. Yang
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/81135035837036097268

碩士 === 國立臺灣大學 === 光電工程學研究所 === 87 === Semiconductor surface gratings with variable periods were successfully fabricated using prism interferometry and holographic methods. The light source for interfoerometry fringes was the fourth harmonic of a Q-switched Nd:YAG laser with wavelength at 266 nm. Surface morphology and composition of laser-induced semiconductor gratings were studied. It was found that the mechanisms for the formation of silicon surface gratings depended on ambient gases and laser intensity. Meanwhile, intermixing of GaAs/AlGaAs multiple quantum wells utilizing the technique of pulsed photo-absorption induced disordering was successfully implemented with a pulsed Ti:sapphire laser. Large blue shifts of bandgap up to 150 meV were obtained in our experiments. Also, this technique was used to fabricate channel waveguides. The near-field patterns demonstrated the wave-guiding effect induced by spatially selective quantum well intermixing.