Quantum optical oscillations of the Fermi level in a graphene-based Schottky junction

Abstract

The strong movility of charge carriers in graphene allows the introduction of high doping concentration in this material and, this way, the Fermi level can be tunned over a large range of energies. The above situation acquires a complex character in presence of strong electron–photon interaction that induces new quantum phases. In this context, this work describes the possible quantum oscillatory behavior of the Fermi level for a graphene-silicon Schottky junction under circular polarized radiation in the terahertz regime. The reported quantum optical oscillations of the Fermi level are related to intraband optical transitions of intrinsic photon-dressed electrons in the graphene sheet, which promote shiftings of the spectral singularities in the density of states (DOS). In addition, the oscillatory effect is strongly accented in the number of oscillations and modulation by the induction of electrons from the semiconductor to the graphene sheet via a gate potential.