The effect of Auger heating on intraband carrier relaxation in semiconductor quantumrods

TL;DR

This paper reports the first experimental observation of Auger heating in CdSe quantum rods, revealing how it influences carrier relaxation and cooling dynamics at high excitation intensities, with implications for nanoscale device performance.

Contribution

It demonstrates for the first time that Auger heating significantly affects carrier relaxation in semiconductor quantum rods, a phenomenon not previously observed in bulk or nanoscale semiconductors.

Findings

Auger heating leads to reduced carrier cooling rates.

Carrier temperature reaches equilibrium between phonon emission and Auger heating.

Cooling dynamics are closely linked to recombination processes.

Abstract

The rate at which excited charge carriers relax to their equilibrium state affects many aspects of the performance of nanoscale devices, including switching speed, carrier mobility and luminescent efficiency. Better understanding of the processes that govern carrier relaxation therefore has important technological implications. A significant increase in carrier-carrier interactions caused by strong spatial confinement of electronic excitations in semiconductor nanostructures leads to a considerable enhancement of Auger effects, which can further result in unusual, Auger-process-controlled recombination and energy-relaxation regimes. Here, we report the first experimental observation of efficient Auger heating in CdSe quantum rods at high pump intensities, leading to a strong reduction of carrier cooling rates. In this regime, the carrier temperature is determined by the balance between energy outflow through phonon emission and energy inflow because of Auger heating. This equilibrium results in peculiar carrier cooling dynamics that closely correlate with recombination dynamics, an effect never before seen in bulk or nanoscale semiconductors.