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(001), (111)A and (111)B surfaces have been studied by means of L EELS (low-energy electron-loss spectroscopy) and AFM (atomic force mic roscopy). GaSe films were grown on the substrates at 400 degrees C usi ng a single evaporation source of GaSe. The evolution of a LEELS spect rum with increase in film thickness reveals a difference in deposition depending on the surfaces. While only GaSe grows on GaAs(111)A and (1 11)B surfaces, the GaAs(001) surface first undergoes a deposition of G a2Se3 subsequently GaSe grows on the thin Ga2Se3. In the AFM images of films with thickness of about 20 Angstrom on GaAs(111)A and (111)B su rfaces, steps with a height of a primitive layer thickness of GaSe are observed, thereby suggesting a primitive layer-by primitive layer gro wth of GaSe.