Electrical Characterization of Silicon — Nickel Iron Oxide Heterojunctions

The electrical properties of Radio Frequency Sputtered NiFeO and NiO films deposited on n and p-type Silicon is investigated for two different oxygen flows. Rectifying properties for Ni 0.8 Fe 0.2 O 1+ α on n-Si showed I forward /I reverse >10,000 for α>0 and I forward /I reverse >50 for α<0. Both types of devices have opposite forward biases. Results suggest that NiFeO sputtered at high oxygen flow is p-type. For NiO and NiFeO on p-Si no strong rectifying properties were observed. The specific contact resistivity of Pt/Ni 0.9 Fe 0.1 O 1+ α (α>0) was estimated from the difference between the two and four-point probe resistances (0.0007 ± 0.0003 Ω cm 2 ). Using density functional theory calculations, density of state and charge density plots were obtained for systems modelled after experiment, showing that states introduced by O vacancies in NiFeO are localized and prefer locations near Ni explaining the observed hysteresis effects in the IV curves of devices sputtered at low oxygen flow.