Dual Role of AgNO₃ as an Oxidizer and Chloride Remover toward Enhanced Combustion Synthesis of Low-Voltage and Low-Temperature Amorphous Rare Metal-Free Oxide Thin-Film Transistors

High Resolution Image Download MS PowerPoint Slide SnO 2 transistors show great promise as an alternative to existing In 2 O 3 -based transistors, considering their abundance and similar electronic properties. However, they suffer from highly negative on-voltages, large subthreshold swings, and high processing temperatures. One of the reasons for this is the residual chloride in the SnO 2 film, which negatively impacts the transistor by increasing the defects or acting as a dopant, thereby shifting the turn-on voltage negatively and increasing the subthreshold swing. Herein, we present a facile method of producing Si x Sn y O films with fewer chloride impurities, which can be used in high-performance, solution-processed TFTs. We employed AgNO 3 as an oxidizer for a low-temperature combustion reaction at 300 °C, which simultaneously acts as a chloride remover. We successfully reduced the turn-on voltage from −35.0 to −0.7 V using this route. The subthreshold swing was decreased from 2.91 to 0.32 V/dec using the same Sn concentration. The highest mobility obtained was 1.92 cm 2 /(V s) from the 0.25 M Sn precursor at a low drain voltage of 0.1 V. This method can be used as a general route for fabricating solution process-based SnO 2 TFTs and further expanding its application to flexible devices via low-temperature combustion.