Improvement of absorption light of laser texturing on silicon surface for optoelectronic application

This work aim to achieving laser nano-textured Si structures by means of an ultra-fast ultra-violet femtosecond (fs) laser texturing technique. The evidences of the impact of the duration of irradiation of the femtosecond laser pulses on Silicon (Si) have been investigated experimentally. A Ti:Sapphire laser at 800 nm (130 fs pulse duration with 1 kHz rate of repetition) has been employed to create nano-textured surfaces in an n-type (111) Si wafer of 0.015 ?.cm resistivity and 508 ? 5 ?m thickness. The average sizes of diameters were estimated to be in the 25-45 nm. From PL measurements of Si nanostructures, size dependent shifts in the direction of the blue spectral region have been emphasized. A highly symmetrical band shape was recognized from the samples? Raman spectra after the irradiation, the phonon frequency (phonon peak shift) shifted below 520 cm-1. The surface nanostructured Si showed lower reflectance values compared with bulk Si (un-irradiated). The observed enhancement of the fabricated Si nanostructures broad spectral response, which is in the range between the visible to the near infrared (NIR) 400-1150 nm, was attributed to increasing light absorption within sub-nanostructures. Thus, the proposed technique could be a promising approach to enhance the performance of Si-based photo-detector.

Automated summary

This work aims to achieve laser nano-textured Si structures using an ultra-fast ultra-violet femtosecond laser technique, with experiments showing the impact of femtosecond laser pulse duration on Silicon. The fabricated Si nanostructures exhibit broad spectral response in the visible to near-infrared range, suggesting potential enhancement for Si-based photo-detectors.