Quantum Carrier Modeling for Gate-tunable Plasmonic

The voltage-tunable carrier density profile (n) of an Indium Tin Oxide (ITO) layer, incorporated as a semiconductor layer in a metal-oxide-semiconductor (MOS) capacitor, is computed via the conventional drift-diffusion (CDD) and Schrödinger-Poisson coupling (SP) models. Under accumulation, the SP model predicts a bump in n which is significantly different from the CDD result. Increasing the voltage switches the real part of permittivity from positive to negative in a region within ITO, creating a metallic layer bounded by epsilon-near-zero (ENZ) point(s). This result has significant implications for plasmonic devices implemented with ENZ materials in a MOS structure.