Preparation and Characterization of CoevaporatedCd1−xZnxSAlloy Thin Films

Abstract

Cd1-xZnxSthin films have been prepared by the vacuum coevaporation method. The structural, compositional, and optical properties ofCd1-xZnxSthin films have been investigated using X-ray diffraction, X-ray fluorescence, and optical transmittance spectra. As-depositedCd1-xZnxSthin films are polycrystalline and show the cubic structure forx=1and hexagonal one forx<1with the highly preferential orientation. The composition ofCd1-xZnxSthin films determined from Vegard's law and quartz thickness monitors agrees with that determined from the X-ray fluorescence spectra. Optical absorption edge of optical transmittance forCd1-xZnxSthin films shows a blue shift with the increase of the zinc content. The band gap forCd1-xZnxSthin films can be tuned nonlinearly withxfrom about 2.38 eV for CdS to 3.74 eV for ZnS. A novel structure for CuInS2-based solar cells with aCd0.4Zn0.6Slayer is proposed in this paper.