1998 APS March Meeting (Los Angeles) Abstract

TITLE:  Initial Heteroepitaxial Growth of GaSe on Silicon(111)

AUTHORS:  Shuang Meng, Brett R. Schroeder, Zurong R. Dai, Fumio S. Ohuchi
and Marjorie A. Olmstead

ABSTRACT:  

Gallium selenide is a layered semiconductor compound of interest for its
potential uses in optoelectronic applications and as a buffer layer in
large lattice-mismatch heteroepitaxy.  We have used X-ray photoelectron
spectroscopy (XPS) and component-resolved X-ray photoelectron diffraction
(CR-XPD) in combination with low energy electron diffraction (LEED) and
transmission electron microscopy (TEM) to study the heteroepitaxial growth
of GaSe on Si(111)7x7.  To understand the initial reaction of the
individual elements with the Si surface, we have also studied Se
deposition on Si(111).  Our XPD studies reveal that the initial
interaction of Se with Si(111) does not lead to interdiffusion of Se into
the Si substrate, unlike Si(100) or GaAs(111).  We find that GaSe growth
on Si(111) at 500$^o$C starts with a pseudomorphic bilayer of GaSe that
effectively terminates the substrate dangling bonds.  The bonding is
between Ga and Si, independent of whether or not the surface has been
previously exposed to a Se flux.  XPD shows that this bilayer is oriented
in a single domain, with the Ga-Se bond aligned with the substrate Si-Si
bond.  Lowering the substrate temperature to 450$^o$C results in thicker
film growth under the same exposure conditions; however, a multidomained
film is formed.