Carrier density and mobility fluctuations due to carrier retrapping process in homogeneous semiconductors

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 out how the capture-emission process affects the free charge carrier mobility, and how the latter impacts the low-frequency noise level. The carrier mobility dependence on phonon, impurity and carrier-carrier scatterings and mobility change dependence on the electric field were taken into account. It is also shown that fluctuations of the charge carrier density and mobility due capture-emission process are completely correlated, and that their relaxation times are the same as for charge capture-emission process. The general expression for estimation of active capture center density in the sample from the low-frequency noise measurements is presented.