High mobility p-channel tin monoxide thin-film transistors with hysteresis-free like behavior

In this Letter, we report a demonstration of p-channel tin monoxide (SnO) thin-film transistors (TFTs) with high field-effect mobility (μ_FE) exceeding 10 cm²/Vs and hysteresis-free like behavior. We demonstrate that maintaining metallic states before encapsulation is a key process to enhance μ_FE in p-type SnO thin-films. Sustaining this meta-stability involves the following two processes during fabrication: (1) postdeposition annealing (PDA) in two steps and (2) encapsulation in the middle of each PDA. This simple process not only suppresses creation of oxidized states such as adverse Sn⁴⁺ but also facilitates the lateral growth of crystals with improved crystallinity by interfacial energy stabilization. The resultant SnO TFT reveals a record-high μ_FE up to 15.8 cm²/Vs with a negligible hysteresis of 0.1 V. This study suggests a practical route to grant high μ_FE to p-channel SnO TFTs without any dopant or complex postdeposition treatment.