Charge-carrier trapping effect on 1 / f noise in monolayer graphene

The frequency exponent of 1/f noise in graphene-boron nitride heterostructures is known to have multiple extrema in its dependence on the charge carrier concentration. This behavior is explained in the present paper as a result of the charge carrier trapping by impurities in the boron nitride. A kinetic equation for the charge carriers subject to trapping and interacting with acoustic phonons is derived. This equation is solved numerically, and the equilibrium solutions are used to evaluate the frequency exponent according to the quantum theory of 1/f noise. It is found that the frequency exponent does develop several minima and maxima, provided that the trapping probability is sufficiently wide and has a threshold with respect to the charge carrier energy. A detailed comparison with the experimental data is made, and the results are used to estimate the energy threshold and the trapping cross-section.