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The tribology of molybdenum disulfide (MoS 2 )-Sb 2 O 3 -C films was tested under a variety of environmental conditions (ambient 50% RH, 10 -7 Torr vacuum, 150 Torr oxygen, and 8 Torr water) and correlated with the composition of the surface composition expressed while sliding. High friction and low friction modes of behavior were detected. The lowest coefficient of friction, 0.06, was achieved under vacuum, while sliding in 8 Torr water and ambient conditions both yielded the highest value of 0.15. Water vapor was determined to be the environmental species responsible for high friction performance. XPS evaluations revealed a preferential expression of MoS 2 at the surface of wear tracks produced under vacuum and an increase in Sb 2 O 3 concentration in wear tracks produced in ambient air (50% RH). In addition, wear tracks produced by sliding in vacuum exhibited the lowest surface roughness as compared to those produced in other environments, consistent with the picture of low friction originating from well-ordered MoS 2 layers produced through sliding in vacuum.

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.