Nanostructures with good photoelectric properties fabricated by femtosecond laser and secondary sputtering on ITO films

Abstract The fabrication of uniform and intact nanostructures on semiconductor thin films is an essential process to alleviate the many electronic defects that are usually present. In this study, nanostructures with good photoelectric properties were fabricated on ITO films by direct laser irradiation and secondary sputtering. A Nd:YLF femtosecond laser system, with a wavelength of 800 nm and a repetition rate of 1 kHz based on pulse regenerative amplification, was used. Laser-induced periodic surface structures with different fluences and scan speeds were studied. With a fluence of 1.86 J cm−2, a scan speed of 1.1 mm s−1, a scan spacing of 4.5 μm, and a focused laser spot of 18.5 μm, a large area of uniform nanostructures with little damage are obtained under optimized parameters. The transmittance increases by up to 21%, and the sheet resistance increases more than 10 times. A definite thickness of the ITO thin film was sputtered by secondary sputtering to improve the electrical conductivity, and the heights of nanostructures can be exactly controlled. Compared with the untreated surface of ITO films, the transmittance increases by 19% and the sheet resistance decreases to less than 1.6 times with the optimal nanostructure height of 90 nm. This method to fabricate nanostructures can greatly improve the photoelectric properties without any complex processing and expensive cost, which can be greatly used in a wide area of the industry application.