Highly stable passivation of a Si(1 1 1) surface using bilayer-GaSe

As a stable and 'epitaxial' passivation of a Si surface, we propose the bilayer-GaSe termination of a Si(111) surface. This surface is fabricated by depositing one monolayer of Ga on a clean Si(111) surface and subsequent annealing in a Se flux at around 520 degreesC, which results in unreconstructed 1 x 1 termination of the Si(111) surface by bilayer-GaSe. We found by scanning tunneling microscopy observation that slow cooling of the clean Si(111) surface from 850 to 520 degreesC with simultaneous deposition of a Ga flux results in better termination of the Si(111) surface. It was also found that this surface is stable against heating around 400 degreesC in O-2 atmosphere of 3 x 10(-3) Pa. By utilizing these properties of the bilayer-GaSe terminated surface, we have succeeded in fabricating ZnO quantum dots on this substrate. (C) 2002 Elsevier Science B.V. All rights reserved.