Growth of chalcopyrite-structure semiconductors zinc tin arsenide and zinc tin phosphide by molecular beam epitaxy

Present work is focused on the epitaxial growth of two closely related compounds: ZnSnAS2 and ZnSnP2. We focus on two structural modifications in which these materials can be obtained---the ordered structure (known as chalcopyrite) and the disordered (sphalerite) equivalent with the same macroscopic composition.;To our knowledge no one has applied modern growth techniques to the epitaxial growth of AIIBIVCV2 materials in order to obtain high quality thin films. We decided to investigate the growth of thin films of ZnSnAs2 and ZnSnP2 using gas source molecular beam epitaxy (GS MBE).;The most interesting property of ZnSnP2 is a large difference in the bandgap of material depending on the degree of ordering. The bandgap of bulk crystal can change by up to 0.42 eV simply by variation of the growth conditions.;Custom designed MBE system was constructed to provide the necessary growth precursors. Conventional Knudsen cells were build to evaporate zinc, tin and arsenic. Gas lines were added later to supply phosphorus and arsenic. To determine the initial growth condition evaporation experiments were carried out using small pieces of bulk ZnSnP2. Optimum growth temperature was determined be in the range of 300--350°C. After the optimization of the growth process high quality epitaxial layers of ZnSnAs2 were grown on InP(001) substrates with the lattice mismatch of 3.4·10--4 .;Following the developed procedures epitaxial ZnSnP2 was grown on GaAs(001) substrates. We observed a transition from the sphalerite to the chalcopyrite structure with increasing Sn/Zn flux ratio. This transition was investigated in detail by high resolution X-ray diffraction. Room temperature luminescence was observed on partially ordered samples at 1.35 eV. The growth model of ordered and disordered materials was suggested.;High quality superlattices containing sphalerite structure ZnSnP 2 layers and GaAs spacers were grown to demonstrate the possibility of the epitaxial regrowth. In order to obtain quaternary compounds a mixture of arsine and phosphine was used to obtain ZnSn(AsxP1-x) 2 in a wide range of compositions.