In-Situ Metallic Oxide Capping for High Mobility Solution-Processed Metal-Oxide TFTs

Transparent and highly conductive indium-zinc oxide (IZO) was utilized as a metallic capping layer in solution-processed indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs) to enhance their electrical performance. By applying an in-situ metallic oxide (IZO) as a capping layer, which can be monolithically patterned with source/drain electrodes, the IGZO TFTs have shown enhanced mobility as high as ~60 cm2/V-s, subthreshold slope of <;0.1 V/decade, and threshold voltage of ~1-2 V. We found that metallic capping layers having work function lower than that of the channel material can induce a significant reduction in series resistance and enhance the apparent field-effect mobility of the device.