Nanosecond laser-induced periodic surface structures on wide band-gap semiconductors

摘要

In this work we report on fabrication of laser-induced periodic surface structures (LIPSS) on different semiconductors with bandgap energies in the range of 1.3-3.3 eV and melting temperatures from 1100 to 2700 ℃. In particular, InP, GaAs, GaP and SiC were irradiated in air with nanosecond pulses using a linearly polarized laser beam at 266 nm (6 ns pulse width). The nanostructures, inspected by atomic force microscopy, are produced upon multiple pulse irradiation at fluences near the ablation threshold. LIPSS are perpendicular to the laser polarization direction and their period is of the order of the irradiation wavelength. It was observed that the accumulative effect of both fluence and number of pulses needed for LIPSS formation increased with the material bandgap energy. These results, together with estimations of surface temperature increase, are discussed with reference to the semiconductor electrical, optical and thermal properties.