Influence of an external electric field on the energy dissipation at the initial stage of laser ablation

TL;DR

This paper investigates how an external electric field influences energy dissipation during the initial phase of laser ablation in silicon, using a two-temperature model and comparing two different approaches to account for electric field effects.

Contribution

It introduces and compares two novel modeling approaches for electric field effects in laser ablation, validated against experimental data.

Findings

Both approaches show similar trends in optimizing laser ablation with electric fields.

The first approach aligns well with experimental results, indicating the importance of ambipolar diffusion.

Charge separation effects significantly influence energy dissipation during laser ablation.

Abstract

A density-dependent two-temperature model is applied to describe laser excitation and the following relaxation processes of silicon in an external electric field. Two approaches on how to describe the effects of the external electric field are presented. The first approach avoids the buildup of internal electric fields due to charge separation by assuming ambipolar diffusion and adds an additional carrier-pair current. In the second approach, electrons and holes are treated separately to account for charge separation and the resulting shielding of the external electric field inside the material. The two approaches are compared to experimental results. Both the first approach and the experimental results show similar tendencies for optimization of laser ablation in the external electric field.