A novel deposition technique for compound semiconductors on highly porous substrates: ILGAR

ILGAR (ion layer gas reaction), a novel low-cost technology for the prepara tion of sulfidic thin layers is described, which can be analogously applied for other chalcogenides. The process consists of three steps: (1) applicat ion of a precursor solution on a substrate by dipping or spraying, (2) dryi ng in an inert gas stream, (3) sulfurization of the solid precursor (e.g. a metal halide) by hydrogen sulfide gas. This cycle is repeated until the de sired layer thickness is obtained. Not only on smooth, but also on structur ed and porous substrates the method allows the deposition of homogenous thi n films following the microscopic structure, where other methods often have problems with shading. Once the film is closed, the growth per dip cycle i s constant and reproducible during the process. The binary compounds CdS, C u2S, In2S3 and also the ternary CuInS2 have been prepared by ILGAR on glass and on porous TiO2 or SiO2. The layers were characterised by XRD, SEM and EDX. (C) 2000 Elsevier Science S.A. All rights reserved.