Some Optical Properties of CdSe Single Crystals

Abstract

Optical transmission and reflection measurements were made on a single crystal of CdSe (crystal class $C_{6v}$) with light polarized parallel and perpendicular to the $c$ axis. The absorption coefficients, ${\mu }_{\perp }$ and ${\mu }_{\mathrm{II}}$, were determined and are presented as functions of incident photon energy, at room temperature. The selection rule, ${\mu }_{\perp }>{\mu }_{\mathrm{II}}$, expected for all solids in the crystal classes $C_{\mathrm{nv}}$ and $C_n$, where $n=3, 4, or 6$, is very well obeyed in CdSe. The absorption coefficients are not simple functions of the photon energy, but are nearly exponential and almost follow Urbach's rule.