Interfacial reactivity of Au, Pd, and Pt on BiI3 (001): implications for electrode selection.

Understanding the contact-semiconductor interface is important in determining the performance of a semiconductor device. This study investigated the contact chemistry of BiI(3) single crystal with Au, Pd, and Pt electrodes using X-ray photoelectron spectroscopy (XPS), a technique widely used to probe the interfacial chemistry of many materials. Chemical reactions were identified on the BiI(3) surface for the case of Pd and Pt contacts, while Au showed no reactivity with BiI(3). The difference in reactivities correlated with different surface morphologies of the contact on the BiI(3) surface, which was evidenced by atomic force microscopy (AFM) characterization. The dark resistivity of the BiI(3) crystal with above contact materials was measured by I-V characterization. The highest resistivity was obtained when Au was employed as the contact. These results suggest that Au is better than Pd and Pt as the contact material for BiI(3) single crystal.