Modification of electronic and chemical structure at metal/cdte interfaces by pulsed laser annealing

Abstract

We have measured the effects of metallization and thermal processing on the chemical interaction, band bending, and deep level formation at Au and In/CdTe interfaces using soft x-ray photoemission, photoluminescence, cathodoluminescence, and surface photovoltage spectroscopies. Metallization and laser processing induce major increases in the intensity of several deep photoluminescence transitions. Core level shifts and cathodoluminescence spectra show Fermi level movements characteristic of both a classical work function model and chemically-induced defect pinning. Both interfaces displayed staged Fermi level movements with the evolving metal-semiconductor interaction. Intermediate and final Fermi energies for both systems correlated with the energies of the processing-enhanced photoluminescence transitions, suggesting that the states associated with these transitions are determining the Fermi level.