Chemical bath deposition of nanocrystalline (111) textured Ag2Se thin films

An inexpensive chemical bath technique for nanocrystalline Ag,Se thin films deposition on transparent polyester sheets is developed. The deposition process is essentially based on a hydrolytic decomposition of selenosulfate. The deposited films were characterized by X-ray analysis, and also optical and electrical investigations were performed. X-ray analysis of the films confirmed that the deposited material is (111) textured silver selenide, with an average crystal size of 9.2 nm. The sheet resistance of the annealed films is about 10 Omega/square, while for the as-deposited ones, it is about 20 times higher. The optical investigations show that the films exhibit gradually increasing transparency in the 320-820 nm region. Using the optical absorption data, the optical band gap for the deposited thin films was determined to be 1.8 eV. Such somewhat higher value than the previously reported ones is attributed to size quantization effects. (C) 2000 Elsevier Science B.V. All rights reserved.