Low-Temperature and Solution-Processable Zinc Oxide Transistors for Transparent Electronics

Zinc oxide (ZnO) thin-film transistors (TFTs) have many promising applications in the areas of logic circuits, displays, ultraviolet detectors, and biosensors due to their high performances, facile fabrication processing, and low cost. The solution method is an important technique for low-cost and large fabrication of oxide semiconductor TFTs. However, a key challenge of solution-processable ZnO TFTs is the relatively high processing temperature (>= 500 degrees C) for achieving high carrier mobility. Here, facile, low-cost, and solution-processable ZnO TFTs were fabricated under the annealing temperature of <= 300 degrees C. Dense and polycrystalline ZnO films were deposited by the spin-coating method. The ZnO TFTs showed the maximum electron mobility of 11 cm(2)/V s and a high on/off ratio of >10(7) when the ZnO thin films were annealed at 300 degrees C. The mobility was extremely high among solutionprocessable undoped ZnO TFTs reported previously, even better than some high-cost indium-doped ZnO TFTs fabricated at low temperature. Furthermore, it is found that the mechanism of oxygen vacancies dominates the electron transport in ZnO thin film and interface behaviors of ZnO thin film and SiO2 gate insulator, and then dominates the performances of devices.