Laser-induced optical changes in amorphous multilayers

TL;DR

This paper investigates how laser-induced intermixing enhances the blue-shift of the absorption edge in amorphous multilayers, enabling improved spatial patterning for optoelectronic applications.

Contribution

It demonstrates that laser-induced intermixing further enhances the absorption edge shift in amorphous multilayers, with different mechanisms identified for different material systems.

Findings

Laser-induced intermixing enhances the blue-shift of the absorption edge.

Photo-effects contribute to intermixing in As6Se94/Se80Te20 multilayers.

Thermal effects dominate in Si/Ge multilayers.

Abstract

It is shown that the well-known blue-shift of the fundamental absorption edge in as-deposited compositionally modulated amorphous Si/Ge and As6Se94/Se80Te20 multilayers (with periods of 4-8 nm) is further enhanced due to the thermal or laser-induced intermixing of adjacent layers. The laser-induced intermixing process, as supported by experiments and model calculations, can be attributed to both the local heating and photo-effects in As6Se94/Se80Te20 multilayers, while only the thermal effects were observed for Si/Ge multilayers. Structural transformations, based on this enhanced interdiffusion, provides good capability for spatially patterning optoelectronic devices and digital information recording.