Some Selection Rules for Band-Band Transitions in Wurtzite Structure

Abstract

Optical selection rules at k = (0, 0, 0) in the wurtzite structure are discussed. These rules suggest an interpretation of recently reported work on CdS by Dutton and Lempicki on reflection spectra, and the excitation spectrum of edge emission in polarized light. Assuming band-band transitions at k = (0, 0, 0) are involved, a valence band spin-orbit splitting of 0.0167 ev and crystal field splitting of about 0.070 ev (at liquid ${\mathrm{N}}_2$ temperature) are obtained for CdS. Other predictions of the model and other possible interpretations of the data are discussed.