Enhancing the Performance of Solution-Processed Thin-Film Transistors via Laser Scanning Annealing

In this article, laser scanning annealing is used for the fabrication of solution-processed tungsten–zinc–tin-oxide thin-film transistors (WZTO TFTs) with low temperatures and fast processing. The high-transient intensity of the scanning laser is beneficial to the effective conversion of precursors to metal–oxide lattices, which is also verified by the X-ray photoelectron spectroscopy analysis. Moreover, no apparent phase transformation and lattice expansion exist during laser irradiation of stable amorphous structures of a-WZTO thin films, as observed from the results of X-ray diffraction, Raman scattering spectroscopy, and transmission electron microscopy. Based on laser scanning techniques, the large optical band gap (3.88 eV) is an important factor to realize a high optical performance of WZTO TFTs. The solution-processed WZTO TFT with laser scanning annealing exhibits much better performance with high mobility (up to 4.99 cm2 V–1 s–1), compared to that with thermal annealing (1.27 cm2 V–1 s–1). More importantly, this method is applicable for a wide range of metal–oxide semiconductors and polymer substrates, by solving the incompatibility between solution-processed metal–oxide semiconductors and polymer substrates because of high processing temperatures. Therefore, it shows tremendous potential to be applicable for a wide range of sensors, displays, and circuits. These results demonstrated that the laser scanning annealing provides a promising tool to simplify the fabrication of low-temperature polycrystalline oxide TFTs, when simultaneously utilizing the metal–oxide–semiconductor TFT and low-temperature polycrystalline silicon TFT processes with low cost and high yield.