Structural and transport properties of CdS films deposited on flexible substrates

We report on structural and electrical properties of US films chemically deposited at temperatures 60-70 degreesC from solutions containing cadmium citrate complex-ions and thiourea. We demonstrated the material deposition on a variety of flexible substrates, including viewfoils, cloth, and threads and fabricated devices on the deposited films including solar cells, stress sensors, and photoconductive sensors. Scanning electron microscopy and high resolution transmission electron microscopy data show that the films consist of nanocrystalline grains. The X-ray diffraction data identify crystalline US with hexagonal structure with a very high degree of crystallinity. The relative intensity of the peaks in the X-ray spectrum shows that the crystallites are oriented. The nanostructure of the US films results in a giant reproducible sensitivity to stress (tension) under UV illumination. (C) 2002 Elsevier Science Ltd. All rights reserved.