FERMI-LEVEL PINNING AND CHEMICAL STRUCTURE OF INP-METAL INTERFACES.

Abstract

SOFT X-RAY PHOTOEMISSION SPECTROSCOPY (SXPS) HAS BEEN USED TO INVESTIGATE THE DEPENDENCE OF FERMI-LEVEL PINNING ON CHEMICAL STRUCTURE AT INP-METAL INTERFACES. SXPS CORE LEVEL SPECTRA OF AL, TI, NI, AU, PD, AG, AND CU ON UHV-CLEAVED INP(110) SURFACES REVEAL EVIDENCE FOR SEMICONDUCTOR OUTDIFFUSION, METAL INDIFFUSION, METAL-ANION BONDING AND METAL-CATION ALLOYING. CORRESPONDING FERMI-LEVEL MOVEMENTS INDICATE A RANGE OFPINNING POSITIONS AT SIGNIFICANTLY DIFFERENT ENERGIES WITHIN THE N-TYPE INP BAND GAP. THESE RESULTS DEMONSTRATE THAT THE SCHOTTKY BARRIER HEIGHTS DEPEND SENSITIVITY ON CHANGES IN INTERFACE CHEMICAL BONDING AND DIFFUSION, WHICH STRONGLY AFFECT THE TYPE OF ELECTRICALLY ACTIVE SITES AND INTERFACIAL LAYERS FORMED.