ABSTRACT -- The objective of this research is to construct the prototype of room-temperature photoreflectance (PR) spectroscopy measurement system for studying the energy band structures of semiconductor and semiconductor heterostructures. The system is set up on an optical table and modulation light is provided by a 3 mW He-Ne laser. The chopped laser light is irradiated onto the thin film sample. Light from a 100 W tungsten lamp passed through a 7 cm monochromator, acts as a probe light. The reflected probe light from the sample is detected for each wavelength from 500 nm to 2200 nm. The detected signal has two parts: The ac part measured by the lock-in amplifier synchronize to the modulating frequency is related to the change in reflectivity, dR, while its dc part is related to the reflectivity, R. Using a computer for control system and data acquisition, a spectrum of dR/R versus photon energy can be obtained.

KEYWORDS -- photoreflectance, spectroscopy, energy band structures, semiconductor