Charge carrier mobility fluctuations due to the capture–emission process

Abstract

It is shown that the free charge carrier capture–emission process causes both the charge carrier density and mobility fluctuations. In this report we present the calculation results in order to find how the capture–emission process affects the free charge carrier mobility and mobility fluctuations. The carrier mobility dependence on phonon, impurity and carrier–carrier scatterings, and the mobility dependence on the electric field and the energy gap variation due to the doping level were taken into account. It is also shown that fluctuations of the charge carrier density and mobility due to the capture–emission process are completely correlated, and that their relaxation times are the same as for the charge capture–emission process. The general expression for estimation of active capture centre density in the volume of a homogeneous sample from the low-frequency noise measurements is presented.