Effects of iodine doping on structural and electrical characteristics of solution-processed indium oxide thin-film transistors and its potential application for iodine sensing

Abstract

This study investigated the influence of solution-processed indium oxide (In₂O₃) thin-film transistors (TFTs) with various iodine vapor (I₂) doping times. Prolonged iodine doping time is found to induce some important changes in the devices: (i) increase in In₂O₃ film thickness and nanoparticle size; (ii) decrease in the metal-hydroxyl bonding and increase in the metal–oxygen bonding; (iii) the positive moved threshold voltage, lower field-effect mobility, and higher on/off current ratio from 0 s (sec) to 10 s. Furthermore, vacuum thermal treatment, as a facial, novel method to recover the electrical performances of I₂-doped In₂O₃ TFTs was examined. I₂-doped In₂O₃ TFTs for 10 s with vacuum thermal treatment at 200 ℃ exhibited excellent recovery properties of electrical. The results indicate that iodine doping can change the electrical properties of In₂O₃ TFTs and could potentially be used for I₂ gas sensor.