Selenium 4p orbital enables high-mobility p-type tin oxyselenide semiconductor for thin-film transistor applications

Abstract

Development of p-type inorganic semiconductors for high performance thin-film transistor (TFT) can be an essential ingredient for next-generation display applications which requires a low power consumption. However, the conventional p-type oxide semiconductors exhibit the poor electrical characteristics, which is mainly attributed to the inefficient conduction path formation from oxygen 2p orbitals. Here, we report a new p-type material, tin oxyselenide (SnSeO) semiconductors for high performance p-channel TFTs. The SnSeO was designed with the concept that valence band maximum (VBM), hole conduction path, becomes delocalized by hybridizing selenium 4p and tin 5s orbitals. The SnSe0.56O0.44 thin-film exhibited the highest Hall mobility of 15.0 cm2 V-1 s-1 and hole carrier density of 1.2 x 1017 cm-3. In addition, the SnSe0.56O0.44 TFT showed the excellent field-effect mobility of 5.9 cm2 V-1 s-1 and current modulation ratio of 3.0 x 102. This high mobility is explained by the low hole effective mass through valence band engineering, which was confirmed by density functional theory calculation. Moreover, complementary metal oxide semiconductor (CMOS) inverter using the p-type SnSe0.56O0.44 with n-type IGZO showed excellent intrinsic gain of 15.7. This anion hybridization can provide a facile route to the realization of a high performance p-channel TFT for next-generation displays.