Orientation dependent surface damage observed in laser irradiated cadmium telluride

Cadmium telluride has been irradiated with pulses from a Q-switched ruby laser with a homogenised beam. Single pulse irradiations of CdTe produce a non-uniform rippled surface indicative of melting. As the energy density is increased the ripple size increases and linear surface features (LSF) appear. After multiple pulses of one energy density, the linear features occur even at the lower incident energy densities. The linear features are associated with bulk cracking in the substrate and may be decorated with pits. Irradiations of (111), (110) and (100) faces showed that the energy density threshold for the introduction of LSF is lowest for a (111) oriented surface and highest for a (100) surface. The lowest density of LSF is always observed in this latter surface. The LSF lie parallel to (110) crystallographic planes.