Metal oxide heterojunctions for high performance solution grown oxide thin film transistors

With the continuous development of the next generation display technique, solution-processed thin-film transistors based on metal oxide semiconductors attract researchers’ more and more attentions. Both forming oxide alloys and multi-layer heterojunctions are facilitated to further improve the device performances. Here, employing low temperature and solution processed technique, we alternately stacked InZnO oxide alloy and In2O3 high mobility oxide to form heterojunction transistors. Results showed that the heterojunction device performances depend on the individual oxide layer position in the device structure and the layer number of heterojunctions since they were significantly modulated by the interfacial dipole, gate insulator effect of TFT device, and hall carrier concentrations of heterojunction films. In2O3/IZO heterojunction transistors demonstrated the highest saturation field-effect mobility of 31 cm2 V−1·s−1 which was much higher than those of transistors based on individual In2O3, IZO, and ZnO. Apart from that, a 10 V threshold voltage and a 107 on/off current ratio were achieved for the In2O3/IZO heterojunction transistors. These findings provide a powerful strategy on designing high performance metal oxide channel and a scientific basis for the application of solution processed metal oxide semiconductor heterojunctions in the next generation of electronic devices.