Preparation and properties of polycrystalline CdSxTe1-x Films

It is shown that a complete series of mixed CdSxTe1-x semiconductors can be produced in the form of polycrystalline films by co-evaporation of CdS and CdTe. This finding is in contrast to previous results on single crystals. The films are homogeneous and highly oriented. The structure changes from cubic to hexagonal around x = 0.5. The energy gap depends highly nonlinearly on composition: it is constant between x = 0 and x = 0.5, and increases from 1.4 to 2.4 eV in the second half of the interval. The native resistivity is about 107 Ωcm between x = 0 and x = 0.5, decreases six orders of magnitude around x = 0.5 and stays constant at about 10 Ωcm for the rest of the interval.