Surface micro-nano hydrophobic structuring on silver-coated semiconductor substrate by femtosecond laser irradiation

In this paper, the effect of femtosecond laser irradiation on the wettability of semiconductor materials InAs and GaAs coated with silver film was studied. The experimental results show that the semiconductor material can be transformed from hydrophilic to hydrophobic. Laser power and scanning period play a decisive role in the morphology of micro-nano structures, and different micro-nano structures have different hydrophobicity. The higher the surface roughness is, the greater the contact angle is, and the maximum contact angle can reach 143 & DEG;. The existence of silver film further increases the surface roughness in two different ways. For InAs samples, the existence of silver film does not change the surface morphology of the micro-nano structure, which is fish-scale structure. However, the size of the microstructure is increased, and the hydrophobicity is significantly improved. The contact angle increases from 122.6 & DEG; to 139.8 & DEG;. For the GaAs sample, the existence of the silver film changed the surface morphology of the micro-nano structure. The morphology changed from a laser induced periodic structure to the convex structure, and the contact angle increased from 122 & DEG; to 143 & DEG;. The process can be used for surface modification of semiconductor materials, which is well applied to optoelectronic devices to achieve self-cleaning and anticorrosion functions of the surface and prolong the service life of optoelectronic devices.