Epitaxial growth of hexagonal and cubic CdS on [formula omitted] and 2° off-oriented ( [formula omitted])GaAs and CuInSe 2, and misalignment between [ [formula omitted]] CdS and [ [formula omitted]] GaAs axes

Abstract

Epitaxial growth of CdS was carried out on GaAs and CuInSe 2 substrates in the temperature range 420–760°C using the Cd–H 2S–H 2 system. Hexagonal ∼(3 0 3 ̄ 4) or cubic (1 0 0)CdS single crystals were grown on 2° (±0.3°) off-oriented (1 0 0)GaAs depending upon the growth temperature. The occurrence of the hexagonal (3 0 3 ̄ 4) CdS single crystal could be explained in terms of a minimum lattice-mismatch criterion between the film and substrate; the parallel arrangement between the close-packed planes of CdS and GaAs, i.e., (0 0 0 1)A CdS‖(1 1 1)A GaAs, was realized in one set with a smaller mismatch of the two sets of the close-packed planes. On (1 0 0)GaAs, single crystals of hexagonal CdS were not grown; two sets of ∼(4 0 4 ̄ 5) -oriented hexagonal CdS crystallites, or two sets of ∼(3 0 3 ̄ 4) -oriented hexagonal CdS and cubic (1 0 0)CdS crystallites were grown. At a low temperature (440°C), single crystals of cubic (1 0 0)CdS were epitaxially grown on (1 0 0)GaAs.