The Effects of Cd-atmosphere annealing and Cd-dip treatment on high purity CdTe single crystals have been studied thoroughly. It has been presented that the Cd-dip treatment could change the dominant (A(0), X) peak in PL spectrum for as-grown crystal into (D-0, X) for Cd-dipped crystal. This result shows that the conductivity of specimen has been converted from p-type into n-type. By measuring the reflective spectrum of the Cd-dipped specimen, very clear free-exciton (FE) emission peak has been detected. This observation of FE emission indicates that the CdTe single crystal is of very high purity. (C) 2003 Elsevier Science B.V. All rights reserved.