Abstract
We report low temperature growth of zinc chalcogenides (ZnS and ZnSe) on GaAs by the technique proposed by our group which is to use high velocity molecular beams, i. e., the atoms or molecules supplied themselves have the energy necessary for migration on the growing surface. New type of effusion cells to obtain high velocity beams are described in detail. This technique is successfully used for the growth of ZnSe and ZnS at temperatures less than 200°C. The epitaxial growth were confirmed by observing RHEED pattern. The observed RHEED patterns, especially of chevron or arrowhead ones for ZnS are discussed on the basis of lattice relaxation between the substrate and the epilayer. It has been confirmed by low temperature photoluminescence measurements that high quality epilayers are grown by this method. Secondary ion mass spectroscopy showed the existense of large amount of Ga atoms near the hetero-interface both for ZnS/GaAs and ZnSe/GaAs. The origin of Ga is discussed on the Ga droplets formed on GaAs surface during the thermal cleaning.
