CdZnTe films with thickness above 50 mu m were deposited at temperatures of 200-500 degrees C by Close Space Sublimation method. A peel-off approach has been adopted to study the interface chemistry of CdZnTe thick films. For all the CdZnTe films, the scanning electron microscopy images show the small and round-like grains formed at interface in contrast to the large ordered grains at surface. For CdZnTe films grown at a low substrate temperature of 200 degrees C, the interface layer between CdZnTe and substrate is mixed with Te and CdTe, as evidenced by X-ray diffraction, Raman and X-ray photoelectron spectroscopy results. The thickness of the interface layer can be estimated to be 84 nm by depth profile using X-ray photoelectron spectroscopy. In contrast, a thin interface layer less than 14 nm is found at a high substrate temperature of 500 degrees C. The limited reaction of Te-2 and Cd (Zn) to CdZnTe at a low growth temperature is responsible for the formation of the thick interface layer and a slow deposition rate at the nucleation stage. (C) 2016 Elsevier B.V. All rights reserved.