Studies on solution grown HgxCd1-xS thin films

The chemical deposition process is successfully used to obtain (Cd, Hg) S thin films with varying concentration of both Cd2+ and Hg2+ ions. The films grew in two different phases: one initial quasi linear and the other saturation phase. Thin, uniform, tightly adherent and densely packed deposits are obtained with this technique. The deposits are polycrystals of the hexagonal type HgxCd1-xS solid solution for the range of composition parameter (x) from 0 to 0.15. For the higher values of composition parameter, the formation of separate phases of CdS and HgS occurred. The lattice parameter, c, varies typically from 6.66 to 7.054 Angstrom for the solid solution range only. The optical studies showed displacement in the absorption edge towards the lower energy side. The observed energy gap for CdS is 2.42 eV and it decreased down to 1.76 eV as x is increased from 0 to 0.05. The transition of the band-to-band direct type is found. Scanning electron microscopy revealed two different type of structures mixed together: one that looks like a leafy cabbage type structure (due to growth of hexagonal CdS over cubic) while other with higher sized grains elongated in appearance (due to HgxCd1-xS phase). (C) 1998 Elsevier Science S.A. All rights reserved.