High-Sensitivity ISFETs Enabled by Solution-Processed Indium Oxide and Nanoimprint Transferring Techniques

This study presents a facile approach for fabricating high-performance indium oxide (In2O3) nanosheet thin-film transistors (TFTs) by using a combination of solution processing and nanoimprint transfer techniques. For the first time, nanostructured In2O3─featuring nanowire and honeycomb patterns with line widths as narrow as ∼158 and ∼89 nm, respectively─was successfully realized via a sol–gel nanoimprint strategy. The resulting nanosheet TFTs demonstrated outstanding electrical characteristics, including sharp output current profiles, a high ON/OFF current ratio, and enhanced field-effect mobility. By exploiting the advantages of nanoscale patterning and capacitive coupling in double-gate structures, the study further introduces ultrasensitive In2O3-based ion-sensitive field-effect transistors (ISFETs) for pH sensing, achieving a remarkable sensitivity of approximately −84.1 mV/pH. These findings not only highlight the potential of scalable nanofabrication techniques for oxide electronics but also open exciting opportunities for next-generation biomedical sensors and wearable electronic systems.