Interfacial and electrical properties of solution processed p-TiO2 in heterojunction devices

Interfacial and electrical properties of Ni2+-doped TiO2 thin films were studied. X-ray photoelectron spectroscopy (XPS) indicated the influence of Zn+ 2 ions on the local chemical environment of Ti atoms. The p-type conductivity of the Ni2+:TiO2 was confirmed from the current–voltage relations of Ag/ZnO/Ni2+:TiO2 bipolar and Ag/ZnO/NiO/Ni2+:TiO2/Si field effect transistor (FET) devices. The performance of FET was examined as a function of temperature and evaluated in terms of mobility (μ), hole diffusion coefficient (Dh) and sub-threshold swing (SS). The μ and Dh were 0.1–2.9 cm− 2 V− 1 s− 1 and 10− 3–10− 1 cm2 s− 1, respectively and SS was comparable to a back-gated silicon nanowire FET at around 370–680 mV per decade.

Research Highlights
► Interfacial and electrical properties of Ni2+-doped TiO2 thin films were studied.
► The p-type conductivity of Ni2+:TiO2 was examined with heterojunction devices.
► The performance of FET was evaluated as a function of temperature.