RF Characteristics of Electrochromic, WO3 and NiO Films with LiNbO3 Electrolyte

A great deal of attention has been recently focused on Electrochromic (EC) materials and EC based devices, promoting mostly applications related to display technology1-7. In this case, EC based displays are usually actuated by the application of low dc bias voltages, changing their appearance from transparent to opaque. A variety of studies related to the optical characteristics of EC materials have been reported8-13, however, no serious studies so far have been reported on the possible radio frequency (RF) tunability of the dielectric characteristics of these materials, with the exception of the work by Rose14, which presented the operation of a microwave shutter based on conductive polymers operating in the X-band. Here we report RF characteristics of an Electrochromic (EC) cell with a complimentary structure of Conductor/WO3/LiNbO3/NiO/Conductor in the frequency range from 40 MHz to 20 GHz are reported. The EC cell was prepared using standard semiconductor processing technology, such as lithography, etch and deposition techniques. Our measured results indicate that tunability of RF characteristics is achieved, and that a possibility exists for this tunability to be tailored.