# A new method for measuring excess carrier lifetime in bulk silicon: Photoexcited muon spin spectroscopy

## TL;DR

This paper introduces a novel technique using photoexcited muon spin spectroscopy to measure excess carrier lifetime in bulk silicon, effectively minimizing surface effects and enabling detailed injection- and temperature-dependent analysis.

## Contribution

The paper presents a new method for measuring silicon's carrier lifetime that combines muon spin spectroscopy with optical injection, providing direct bulk measurements.

## Key findings

- Successfully measured bulk carrier lifetime in silicon.
- Demonstrated the method's effectiveness across various injection levels.
- Showed temperature dependence of carrier lifetime using the technique.

## Abstract

We have measured the optically injected excess carrier lifetime in silicon using photoexcited muon spin spectroscopy. Positive muons implanted deep in a wafer can interact with the excess carriers and directly probe the bulk carrier lifetime whilst minimizing the effect from surface recombination. The method is based on the relaxation rate of muon spin asymmetry, which depends on the excess carrier concentration. The underlying microscopic mechanism has been understood by simulating the four-state muonium model in Si under illumination. We apply the technique to different injection levels and temperatures, and demonstrate its ability for injection- and temperature-dependent lifetime spectroscopy.