CdS Reflection Coefficient Determination via Photocurrent Spectroscopy

by Wang, Yang

Reflectance is a very essential property of every semiconductor and the topic of this thesis was to determine the reflection coefficient of CdS by unusual means, i.e., be using photocurrent spectroscopy. Reflectance and photocurrent of the CdS sample and a silicon photodiode was measured using the lock-in amplifier. The photocurrent of the diode was required in order to correct the CdS photocurrent spectra, which are influenced by the experimental setup. By means of photocurrent, the absorption coefficient was determined using the density of states (DOS), Urbach rule, and the appropriate expression for the photocurrent. Measurement and the theory matched very well, and finally, using the absorption coefficient the dispersion of the CdS reflection was plotted.