Solution growth and characterization of silver sulfide films

Silver sulfide (Ag2S) thin films were grown by an electroless chemical deposition technique at 50°C and pH = 10. Silver ions were first complexed by ammonia, and then sodium thiosulfate solution was introduced. Upon hydrolytic decomposition, uniform thin silver sulfide films were grown on either glass or polyester substrates. X-ray studies confirmed that the deposited material was Ag2S. Optical studies were carried out in the spectral region 0.3-2.5 μm. The absorption coefficient of the films was found to decrease with increasing wavelength, which makes the Ag2S films suitable as IR detectors. The optical band-gap energy of the films was found to be 2.2 eV. The resistivity was 14–20 Ω·m, and the films were of p-type.