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 cm(2) V-1 s(-1)), compared to that with thermal annealing (1.27 cm(2) 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.