Laser-assisted patterning of solution-processed oxide semiconductor thin film using a metal absorption layer

We present a method to pattern solution-processed oxide semiconductor thin films by all laser process. A metal thin film is first photoetched by a spatially-modulated pulsed Nd-YAG laser beam and this layer is then covered with a semiconductor film. Uniform irradiation by the same laser generates a thermo-elastic force on the underlying metal layer and this force serves to detach it from the substrate, leaving only a patterned semiconductor structure. Sharp-edged zinc-tin oxide (ZTO) patterns at the micrometer scales could be fabricated over a few square centimeters by a single pulse of 850 mJ. A mobility of 7.6 × 10⁻² cm² V⁻¹ s⁻¹, an on/off ratio higher than 10⁶, and an off-current of 1.91 × 10⁻¹¹ A were achieved from a thin film transistor (TFT) with the patterned ZTO channel. These values were similar to those from a reference TFT, demonstrating the feasibility of this patterning process for electronic devices.