Light Source Control System for Electroreflectance Studies on Semiconductors

Abstract
A feedback source‐control system has been designed for electroreflectance measurements on semiconductors. An amplified dc off‐balance voltage is used to control the light source and compensate for the wavelength variation of the various optical components. The percentage modulated reflectance was therefore measured directly over the experimental wavelength range. The system was applied to infrared measurements of the fundamental edge of GaAs and (Ga, In)As in the wavelength range 8000 to 11 000 Å. The extension of this system to other experiments is discussed.