Tin monoxide as an s‐orbital‐based p‐type oxide semiconductor: Electronic structures and TFT application

作者：Yoichi Ogo, Hidenori Hiramatsu, Kenji Nomura, Hiroshi Yanagi, Toshio Kamiya, Mutsumi Kimura, Masahiro Hirano, Hideo Hosono · 发表于：physica status solidi (a) · 年份：2009 · DOI：10.1002/pssa.200881792 · 被引用次数：254 · 研究领域：ZnO doping and properties、Thin-Film Transistor Technologies、Gas Sensing Nanomaterials and Sensors

Abstract Tin monoxide (SnO) is a stable p‐type oxide semiconductor. This paper reports electrical properties, electronic structures, and thin‐film transistors (TFTs) of SnO. Epitaxial films were fabricated by pulsed laser deposition. The Hall mobility and the hole density of the epitaxial films were 2.4 cm2 V−1 s−1 and 2.5 × 1017, respectively. X‐ray photoelectron spectroscopy (PES) indicated that the closed‐shell 5s2 orbitals of Sn2+ ions heavily contribute to the hole conduction path in SnO. Top gate type TFTs (W/L = 300/50 µm) employing 20 nm thick SnO channels exhibited field‐effect mobilities µsat = 0.7 cm2 V−1 s−1 and µlin = 1.3 cm2 V−1 s−1, which are larger by two orders of magnitude than those reported for p‐channel oxide TFTs to date. On/off current ratios were ∼102 and subthreshold voltage swings (S) ∼7 V/decade. The parameters required for TFT simulations were estimated by ultraviolet PES and first‐principles calculations. The TFT simulations indicated that subgap hole trap density in the SnO channel is >1019 cm−3, which limits the TFT mobilities and the S values.