Carrier thermalization dynamics in single Zincblende and Wurtzite InP nanowires

TL;DR

This study investigates the ultrafast thermalization of photoexcited carriers in single zincblende and wurtzite InP nanowires using transient Rayleigh scattering, revealing material-dependent dynamics influenced by phonon band structures.

Contribution

Developed a phenomenological model to extract carrier density and temperature dynamics from TRS measurements in complex InP nanowires, highlighting material and crystal structure effects.

Findings

Thermalization dynamics are strongly dependent on material composition.

ZB and WZ InP nanowires exhibit similar thermalization behavior.

InP nanowires relax over an order of magnitude slower than GaAs nanowires.

Abstract

Using transient Rayleigh scattering (TRS) measurements, we obtain photoexcited carrier thermalization dynamics for both zincblende (ZB) and wurtzite (WZ) InP single nanowires (NW) with picosecond resolution. A phenomenological fitting model based on direct band to band transition theory is developed to extract the electron-hole-plasma density and temperature as a function of time from TRS measurements of single nanowires which have complex valence band structures. We find that the thermalization dynamics of hot carriers depends strongly on material (GaAs NW vs. InP NW) and less strongly on crystal structure (ZB vs. WZ). The thermalization dynamics of ZB and WZ InP NWs are similar. But a comparison of the thermalization dynamics in ZB and WZ InP NWs with ZB GaAs NW reveals more than an order of magnitude slower relaxation for the InP NWs. We interpret these results as reflecting their distinctive phonon band structures which lead to different hot phonon effects. Knowledge of hot carrier thermalization dynamics is an essential component for effective incorporation of nanowire materials into electronic devices.