MOLECULAR-BEAM EPITAXY OF ZNS USING AN ELEMENTAL S SOURCE

The successful growth of ZnS using elemental sources of Zn and S is reported. This wide band gap semiconductor is difficult to grow by molecular-beam epitaxy (MBE) using elemental sources because of the very high vapor pressure of S. As a consequence, a new type of effusion cell, designed for very low temperature operation, was developed. Techniques for the evaporation and containment of S in the MBE system are also described. ZnS films were deposited onto (100) GaP substrates, with and without ultraviolet radiation incident on the substrate during film growth. High quality epitaxy of semi-insulating ZnS was achieved at temperatures as low as 150-degrees-C by means of photoassisted MBE. N-type ZnS: Cl films were also prepared using ZnCl2 as a solid dopant source. The electrical and optical properties of these epilayers are discussed.