Photoreflectance of AlGaAs/GaAs superlattice

• Main Authors: Hsieh, Kuo-Ping, 謝國屏
• Other Authors: Gwo-Jen Jan
• Format: Others
• Language: en_US
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/10858049551225101709

碩士 === 國立臺灣大學 === 光電工程學研究所 === 86 === The photoreflectance spectroscopic technique was applied to investigate a series of GaAs/AlGaAs superlattice specimens (M series). These specimens gr own by Molecular Beam Eptiaxy (MBE) are of various cap-widths, well and barrie r numbers . The observed fundamental bandgap transition as well as interband t ransition energies were fitted by First Derivative Gaussian Fitting Function t o obtain corresponding optical transition energies and broadening parameters. In addition, calculations of states in the wells based on a Kronig-Penney appr oximation model were performed to give theoretical prediction to compare with experimental results. We also found that in a superlattice system with thin b arrier width as 30( the coupling effect indeed dominates the interband transit ion as predict. Furthermore, we also performed the temperature-dependent photo reflectance experiments to investigate the relationship between the temperatur e variation and transition energies of M-series specimens, it shows that the t emperature variation of transition energies is fitted well with the Varshni eq uation.