We report a first principles investigation of photocurrent generation by graphene PN junctions. The junctions are formed by either chemically doping with nitrogen and boron atoms, or by controlling gate voltages. Non-equilibrium Green's function (NEGF) formalism combined with density functional theory (DFT) is applied to calculate the photo-response function. The graphene PN junctions show a broad band photo-response including the terahertz range. The dependence of the response on the angle between the light polarization vector and the PN interface is determined. Its variation against photon energy Eph is calculated in the visible range. The essential properties of chemically doped and gate-controlled PN junctions are similar, but the former shows fingerprints of dopant distribution.
@article{arxiv.1202.4980,
title = {First-principles Analysis of Photo-current in Graphene PN Junctions},
author = {Jingzhe Chen and Yibin Hu and Hong Guo},
journal= {arXiv preprint arXiv:1202.4980},
year = {2015}
}