AMBIENT SCANNING TUNNELING SPECTROSCOPY OF SULFUR PASSIVATED INP(100)SURFACES

The results of scanning tunnelling spectroscopy (STS) studies of wet c hemical sulphur passivated InP(100) surfaces are presented. The aim of the study was to attempt to establish a more quantitative measure of the surface passivation using the STM. Current voltage (I-V) spectrosc opic plots for sulphur passivated and native oxide surfaces displayed distinct differences previously reported for GaAs(100) surfaces. Curre nt distance (I-S) spectroscopic results for both passivated and unpass ivated InP surfaces and the accompanying apparent barrier height (phi( A)) measurements are presented along with a justification of the resul ts. For reference purposes, phi(A) measurements of the Au(111) surface were made to establish the validity of the (I-S) spectroscopic techni que in air. The chemical composition of the InP(100) surface before an d after sulphur passivation is determined by X-ray photoelectron spect roscopy (XPS) measurements. (C) 1998 Elsevier Science B.V.