  Transparent Conductive Oxides (TCOs) are a class of materials that combine
high optical transparency with high electrical conductivity. This property
makes them uniquely appealing as transparent-conductive electrodes in solar
cells and interesting for optoelectronics and infrared-plasmonics applications.
One of the new challenges that researchers and engineers are facing is merging
optical and electrical control in a single device for developing
next-generation photovoltaic, opto-electronic devices and energyefficient
solid-state lighting. In this work, we investigated the possible variations in
the dielectric properties of aluminum-doped ZnO (AZO) upon gating, by means of
Spectroscopic Ellipsometry (SE). We investigated the electrical-bias-dependent
optical response of thin AZO films fabricated by magnetron sputtering, within a
parallel-plane capacitor configuration. We address the possibility to control
their optical and electric performances by applying bias, monitoring the effect
of charge injection/depletion in the AZO layer by means of in-operando SE vs
applied gate voltage.
