P-type ZnO thin-film transistors and passivation using photoelectrochemical oxidation method

Abstract

A high-performance stable i-ZnO buffer layer and p-ZnO channel layer for p-ZnO thin-film transistors (TFTs) were deposited using vapor cooling condensation. The resulting p-ZnO TFTs had a transconductance of 1.87 × 10−6 S, saturation drain–source current of −14.1 µA, and field-effect mobility of 7.12 cm2 V−1 s−1. To improve the performance, the channel layer was passivated using photoelectrochemical oxidation. The transconductance, saturation drain–source current, and field-effect mobility of the passivated TFTs were improved to 2.05 × 10−6 S, −16.0 µA, and 7.83 cm2 V−1 s−1, respectively. The performance improvement was attributed to the reduced interface state density obtained by passivation.