PASSIVATION OF GAAS(111)A SURFACE BY CL TERMINATION

It is found that an ordered and air-stable GaAs(111)A-(1X1)-Cl surface can be produced by chemical etching/passivation with dilute HCl solut ion. The synchrotron polarization-dependent Cl K-edge x-ray absorption near-edge structure and x-ray photoelectron spectroscopy studies show ed that the surface is terminated with Ga-Cl bonds oriented along the surface normal. Low-energy electron diffraction studies showed a bulkl ike (1X1) structure on the Cl-terminated GaAs(111)A surface. The Cl te rmination eliminates surface band-gap states caused by surface oxides. Photoluminescence measurements showed a dramatic increase in the near -band radiative emission rate corresponding to reduction in the occupi ed surface band-gap states. A reduction of surface gap states by Cl te rmination was confirmed by surface photovoltage measurements. (C) 1995 American Institute of Physics.