p-type conversion of distorted SnOx thin film by mild thermal annealing treatment in pure N2 environment

Abstract

Tin oxide semiconductors can achieve both n- and p-type conduction, depending on the oxidation state of Sn. An n-type conduction can easily be fabricated; however, considerable optimization is required for fabrication of a p-type behavior. In this study, n-type SnOx thin films, prepared by reactive magnetron sputtering, were converted to p-type behavior using only post-deposition annealing at 600 °C in a pure nitrogen atmosphere. The annealing-temperature-dependent electrical properties of the SnOx thin films led to a remarkable increase in the yield of p-type behavior at 600 °C. X-ray diffraction analysis revealed that the SnOx film had a SnO2-dominant crystal phase and also suggested that N2 molecules dissociated at 600 °C and filled the oxygen vacancy (VO) site as atomic nitrogen. A detailed analysis of the binding state by x-ray photoelectron spectroscopy confirmed an increase in SnO-derived components, the appearance of peaks derived from N–Sn bonding, a decrease in VO caused by nitrogen doping, and charge transfer. Thus, we found that addition of nitrogen atoms promotes a chemical shift from Sn4+ to Sn2+ and that simultaneously passivates VO and contributes to hole generation.

Correlation between CO2 Sensitivity and Channel-Layer Thickness in In2O3 Thin-Film Transistor Gas Sensors

“…However, a slight downshift of ~0.5 eV for the M-O component was observed in our In2O3. This shift is possibly caused by electron transfer [42], resulting in decreased carrier density compared to the standard In2O3. As we mentioned above, our oxide films may incorporate Ar + impurities, and they cause a In semiconductor gas sensors, the surface is activated by heating during measurement to enhance reactivity with the surrounding gas [6].…”