Liquid Phase Homoepitaxy of CuInS2

This paper reports the first studies of homoepitaxial growth of CuInS₂ (CIS)-layers by liquid phase epitaxy (LPE). The deposition of the CuInS₂-fılms was carried out on single- and polycrystalline substrates, grown in our laboratory by the travelling heater method (THM).

In the temperature range of 500 - 600 °C, the solubility of CIS in Cu_xIn_lx-melts with different compositions (x = 0 - 0,2) was determined. Melts with a copper content x > 0.05 were used as a solvent to prevent the formation of secondary phases. The epitaxy itself was strongly effected by the process atmosphere: Flowing hydrogen reduces melts, but causes also thermal degradation of the substrate. On the other hand by the use of nitrogen the nucleation is presumably handicapped by native oxides. The best layers were made by a back-etching step under H₂-flow. Two major growth morphologies were observed depending on the substrate orientation.