Orientation of CuGaS2 thin films on (100) GaAs and GaP substrates

CuGaS2 films have been groan on (100) GaAs and GaP wafers by the vacuum evaporation technique using constituent elementary substances as sources. RHEED patterns of the films that use [011] azimuths in a substrate show two different patterns in mutually orthogonal directions, In one direction, the observed pattern is a single pattern which illustrates that CuGaS2 grows in the [001] orientation direction (the c-axis growth). In another direction, however, additional patterns appeared. This phenomenon indicates that one pair of the 180 degrees rotated {112} twins exist in addition to c-axis growth in a film, and it also indicates that additional orientations except fur c-axis growth are reduced in films grown on compound substrates as compared with ones on (100) Si.