The Transistor Characteristics of Zinc Oxide Active Layer with Different Thickness of Zinc Oxide Thin-Film

ZnO is a wide band gap semiconductor which is used as transparent electrode in solar cells, chemical and gas sensors and light emitting diodes etc. This study examines the semiconductor layers produced by ZnO solution with sol-gel method and spin-coating in zinc oxide (ZnO) thin-film transistors (TFTs). By using spin coating method, the films are deposited on Si substrates. Compared with other methods, the method used in this study can be made at low annealing temperature of 300°C. We have investigated the electrical characteristics of ZnO thin film transistors with respect to the different thickness of ZnO active layers: 3.7 nm and 11.7 nm. The film thickness is controlled by the number of spin-coatings. In this study the V_DS-I_DS curve was consistent with ideal metal-oxide-semiconductor field-effect-transistor equation, on-off ratio = 10⁶. The ZnO channel layer with 11.7 mm thickness has the best performance.