Active tuning of the optical response of field-effect-gated transparent conductive oxides

Abstract

Transparent Conductive Oxides (TCOs) are a class of materials with high optical transparency and electrical conductivity. This combination makes them extremely appealing for solar cells, optoelectronics and infrared-plasmonics applications. In this work, we report the active tuning of the optical response of aluminium-doped ZnO (AZO) films upon electrical gating within a parallel-plate capacitor configuration. We investigated the electrical-bias-dependent optical response of thin AZO films fabricated by pulsed laser deposition by means of spectroscopic ellipsometry (SE). Calculations based on an exponentially-decaying spatial distribution of injected/depleted charge density in the AZO film are in accordance with experimental observations, allowing the extraction of the Debye length.