Polarization dependent femtosecond laser modification of MBE-grown III-V nanostructures on silicon

TL;DR

This study demonstrates a novel femtosecond laser technique to control the shape of III-V nanostructures on silicon using polarization, enabling precise nanostructure modifications with observable harmonic signal enhancements.

Contribution

Introduces a polarization-dependent femtosecond laser method for shape control of MBE-grown III-V nanostructures on silicon, a novel approach in nanostructure modification.

Findings

Linear polarization elongates nanostructures beyond 88 nm to over 1 μm

Circular polarization flattens or loops nanostructures to about 195 nm

Harmonic signals from substrate and nanostructures increase with exposure time

Abstract

We report a novel, polarization dependent, femtosecond laser-induced modification of surface nanostructures of indium, gallium, and arsenic grown on silicon via molecular beam epitaxy, yielding shape control from linear and circular polarization of laser excitation. Linear polarization causes an elongation effect, beyond the dimensions of the unexposed nanostructures, ranging from 88 nm to over 1 um, and circular polarization causes the nanostructures to flatten out or form loops of material, to diameters of approximately 195 nm. During excitation, it is also observed that the generated second and third harmonic signals from the substrate and surface nanostructures increase with exposure time.