Substrate orientation dependence of the growth of GaSe thin films on GaAs

The initial stages of the heteroepitaxial growth of GaSe thin films on GaAs(OO11, (1ll)A and (1ll)B surfaces have been studied by means of LEELS (low-energy electron-loss spectroscopy) and AIN (atomic force microscopy). GaSe films were grown on the substrates at 400°C using a single evaporation source of GaSe. The evolution of a LEELS spectrum with increase in film thickness reveals a difference in deposition depending on the surfaces. While only GaSe grows on GaAs(1 11)A and (1ll)B surfaces, the GaAs(OO1) surface first undergoes a depsition of Ga,Se,; subsequently GaSe grows on the thin Ga,Se,. In the ABM images of films with thickness of about 20 A on GaAs(1 11)A and (1ll)B surfaces, steps with a height of a primitive layer thickness of GaSe are observed, thereby suggesting a primitive layer-by primitive layer growth of GaSe.