RF sputtered CuxCd1-xTe thin films: a novel semiconductor alloy

An investigation of the structural, chemical and optical properties of a novel metal-semiconductor alloy based on CdTe and Cu is presented. The samples were prepared as thin films in a magnetron rf sputtering system at various substrate temperatures. On the basis of chemical analyses carried out by Auger spectroscopy and energy dispersive X-ray analysis, it was concluded that a novel semiconducting alloy had been created: Cu_xCd_1-xTe. It was also determined that the crystalline structure and optical band gap of CdTe was not severely affected by the inclusion of Cu atoms for values of x up to 8.0 at.%. On the other hand, it was observed that the transport properties changed drastically since in some cases the resistivity of the films decreased by seven orders of magnitude with respect to pure CdTe films grown in similar conditions. The copper concentration had influence on the mean grain-size of the polycrystalline films and on the appearance of the hexagonal phase