Films of Cu1.8S have been made by flash evaporation. They have a resistivity of 6.2×10−4&OHgr;·cm and an absorption coefficient to 1.5 eV radiation of 1.13×103cm−1. The corresponding quantities for Cu1.8Se are: 1.6×10−4&OHgr;·cm, and 1.18×103cm−1. The resistivity of Cu1.8Te films increases with time.It is found that if during flash evaporation the ratio of partial pressures of Cu and Se at the substrate fluctuates then the film does not have the composition of the charge.Cu1.8S has potential applications for producing transparent conducting coatings on substrateswhich cannot be heated above room temperature.