Laser-Induced Modification of the Surface State and Optical Properties of CdTe Crystals
Optical properties and surface state of semiconductor CdTe crystals subjected to irradiation with nanosecond laser pulses were studied. Ellipsometric parameters Δ and Ψ were measured on two opposite surfaces of (111) oriented CdTe wafers before. The samples were subjected to polishing chemical etching and laser irradiation with energy densities lower and higher than the melting threshold of CdTe. The morphology and structure of CdTe crystals were monitored before and after treatments. Irradiation formed a thin modified surface layer on the both sides of CdTe crystals (Cd- and Te-terminated) with the similar optical constants n and k, respectively. However, the effective thicknesses of such modified layers differed and depended on the chemical and laser treatment conditions and also on the faces of CdTe(111) crystals.
L. V. Poperenko et al., "Laser-Induced Modification of the Surface State and Optical Properties of CdTe Crystals", Advanced Materials Research, Vol. 222, pp. 28-31, 2011