Vertical Oxide Homojunction TFTs of 0.8 V Gated by H3PO4-Treated SiO2 Nanogranular Dielectric

Inorganic solid-state electrolyte film based on H3PO4-treated nanogranular SiO2 with high specific capacitance (8 mu F/cm(2)) is developed for vertical indium-tin-oxide (ITO) homojunction thin-film transistors (TFTs) fabrication. Such proton conductor reduces the operating voltage of the vertical homojunction TFTs to 0.8 V due to the enhanced electric-double-layer capacitance. Vertical ITO TFTs gated by such dielectric exhibit a good performance, such as a high current output (> 10 mA/cm(2)), a small subthreshold swing (< 80 mV/dec), a good ohmic contact, and a large on-off ratio (similar to 10(6)). These low-voltage TFTs are very promising for next-generation battery-powered portable sensors.