Transport and Optical Properties of Single- and Bilayer Black Phosphorus with Defects

Shengjun Yuan, A. N. Rudenko, M. I. Katsnelson

Published 2014-11-06Version 1

We study the effect of various kinds of defects on the transport and optical properties of single- and bilayer black phosphorus (BP) by using the large-scale tight-binding propagation method. The impurity states caused by resonant scatterers form sharp peaks in the density of states within the band gap (midgap states), which is different from the uniform increase of states caused by non-resonant scatterers. For both types scattering defects, the impurity states are insulating due to the Anderson localization, and lead to extra excitations within the optical gap. The dc conductivity as well as carrier mobility beyond the gap are reduced significantly because of the scattering from the defects. The angle-dependent absorption coefficients of linearly polarized light show that the anisotropic optical response above the band gap are robust against disorder, but the anisotropy of the defect-induced excitations is restrained. Our transport calculations also suggest that single- and bilayer BP are suitable for the applications as $n$-doped and $p$-doped field-effect transistors, respectively.