Study of the formation and decay of electron-hole plasma clusters in a direct-gap semiconductor CuCl

TL;DR

This study uses numerical solutions of the master equation to analyze electron-hole plasma cluster formation in CuCl, revealing significantly smaller cluster sizes than in indirect-gap semiconductors like Ge and Si.

Contribution

It provides a detailed numerical investigation of cluster formation and decay in CuCl, challenging previous claims of electron-hole droplet formation in this material.

Findings

Average number of pairs per cluster is about 5.2.

Cluster sizes are much smaller than in indirect-gap semiconductors.

Results question the existence of large electron-hole droplets in CuCl.

Abstract

The master equation for the cluster-size distribution function is solved numerically to investigate the electron-hole droplet formation claimed to be discovered in the direct-gap CuCl excited by picosecond laser pulses [Nagai {\em et al.}, Phys. Rev. Lett. {\bf 86}, 5795 (2001); J. Lumin. {\bf 100}, 233 (2002)]. Our result shows that for the excitation in the experiment, the average number of pairs per cluster (ANPC) is only around 5.2, much smaller than that (10$^6$ typically for Ge) of the well studied electron-hole droplet in indirect-gap semiconductors such as Ge and Si.