Generation-recombination processes via acoustic phonons in a disorded graphene

TL;DR

This paper investigates how acoustic phonons facilitate generation-recombination processes in disordered graphene, analyzing rates and relaxation times considering disorder and doping effects at room temperature.

Contribution

It provides a detailed analysis of generation-recombination processes via acoustic phonons in disordered graphene, including calculations of rates and relaxation times for various doping levels.

Findings

Generation-recombination rates are comparable to thermal radiation effects.

Relaxation times range from 150 to 400 ns depending on disorder and doping.

Disorder enables processes forbidden in perfect graphene.

Abstract

Generation-recombination interband transitions via acoustic phonons are allowed in a disordered graphene because of violation of the energy-momentum conservation requirements. The generation-recombination processes are analyzed for the case of scattering by a short-range disorder and the deformation interaction of carriers with in-plane acoustic modes. The generation-recombination rates were calculated for the cases of intrinsic and heavily-doped graphene at room temperature. The transient evolution of nonequilibrium carriers is described by the exponential fit dependent on doping conditions and disorder level. The characteristic relaxation times are estimated to be about 150 - 400 ns for sample with the maximal sheet resistance ~5 kOhm. This rate is comparable with the generation-recombination processes induced by the thermal radiation.