Rutherford backscattering spectrometry was performed using 2 MeV alpha-particles, to characterize electroless platinum contacts on cadmium telluride CdTe(111) crystals, aiming to improve and to understand the structure of the metal electroless chemically deposited. In this paper we have studied the platinum metal contact as well as the interface material-contact. The thickness, the stoichiometry and the concentration profile of platinum, cadmium, tellurium and oxygen present in the surface layers were determined as a function of many parameters, especially the variation trend as function of the chloride solution pH. This work showed the important effect of the crystallographic direction on the growth of Pt on CdTe II-VI semiconductors. Furthermore, the process was more pH dependence at the metalloid Te face than the Cd one. (C) 2007 Elsevier B.V. All rights reserved.