Integration of high-κ native oxides of gallium for two-dimensional transistors
摘要
The deposition of a metal oxide layer with good dielectric properties is a critical step in fabricating the gate dielectric of transistors based on two-dimensional semiconductors. However, current techniques for depositing ultrathin metal oxide layers on two-dimensional semiconductors suffer from quality issues that can compromise transistor performance. Here, we show that an ultrathin and uniform native oxide of gallium (Ga2O3) that naturally forms on the surface of liquid metals in an ambient environment can be prepared on the surface of molybdenum disulfide (MoS2) by squeeze-printing and surface-tension-driven methods. The Ga2O3 layer possesses a high dielectric constant of around 30 and equivalent oxide thickness of around 0.4 nm. Due to the good dielectric properties and van der Waals integration, MoS2 transistors with Ga2O3 gate dielectrics exhibit a subthreshold swing down to 60 mV dec−1, an on/off ratio of 108 and a gate leakage down to around 4 × 10−7 A cm−2.