Tuning the electrical performance of solution-processed In2O3TFTs by low-temperature with HfO2-PVP hybrid dielectric

Abstract

Here in, we investigated the solution-processed and hysteresis-free indium oxide (In2O3) thin-film transistors (TFTs) fabricated with hafnium oxide-poly(vinyl)phenol (HfO2-PVP) hybrid thin film as gate dielectric by a low temperature sol-gel method. The hybrid dielectric thin film exhibits unique dielectric properties of a low leakage current density of 1.2 × 10−8 A/cm2, gate areal capacitance of 44.4 nF/cm2 and a dielectric constant (k) of 6.5 at 1 kHz. In addition, the hybrid films show a high-quality homogeneous and pin-hole free surface with a low surface roughness (Rq) of 0.75-nm and display a low surface energy of 36.7 mJ/m2 with hydrophobic behavior. This dielectric material is then used used in In2O3 TFTs as the gate insulator. Here, the In2O3 semiconductor as the channel layer is examined at 200 °C and 230 °C temperatures for TFT characteristics. The final TFT device fabricated at 230 °C showed much improved electrical performance with the mobility (μsat) of 2.6 cm2/V.s, Ion/Ioff ratio of 105, subthreshold swing (SS) of 330 mV/dec, threshold voltage (VT) of 0.1 V at a low operating voltages because of a better interface between dielectric and semiconductor with fewer charge carriers traps. This study could be an effective approach for the next generation of all-solution fabrication of TFTs that could play a vital role in optoelectronics applications.