Nickel layers on indium arsenide

We report here on the preparation and characterization of InAs substrates f or in situ deposition of ferromagnetic contacts, a necessary precursor for semiconductor devices based on spin injection. InAs has been grown on InAs( 111)A and (100) substrates by molecular-beam epitaxy and then metalized in sim in order to better understand the mechanisms that inhibit spin injectio n into a semiconductor. Initial x-ray characterization of the samples indic ate the presence of nickel arsenides and indium-nickel compounds forming du ring deposition at temperatures above room temperature. Several temperature ranges have been investigated in order to determine the effect on nickel-a rsenide formation. The presence of such compounds at the interface could gr eatly reduce the spin-injection efficiency and help elucidate previous unsu ccessful attempts at measuring spin injection into InAs. (C) 2000 American Vacuum Society. [S0734-211X(00)06804-9].