Deposition of Se and GaSe on surfaces was studied with low-energy electron diffraction, x-ray photoelectron spectroscopy, and x-ray photoelectron diffraction to probe initial nucleation and interface structure for heteroepitaxy. Room-temperature deposition of Se on results in an amorphous film. Subsequent annealing leads to Se evaporation without ordering or interdiffusion. Se deposition at saturates at submonolayer coverage with no diffusion of Se into the substrate. There is no clear evidence of ordered sites for the Se. Growth of GaSe on above results in a pseudomorphic bilayer, with Si-Ga-Se bonding. Additional GaSe does not stick to the bilayer above The resulting Se lone pair at the surface leads to an ideally passivated surface similar to This stable surface is similar to the layer termination in bulk GaSe. The single domain bilayer is oriented with the Ga-Se bond parallel to the substrate Si-Si bond.
- Received 5 August 1999
- Revised 7 December 1999
- Published in the issue dated 15 March 2000
© 2000 The American Physical Society