KSEF RDE: Searching for New Transparent Conducting Oxides via Plasma Hydrogenation

Transparent conducting oxides (TCO's) are the key materials utilized in optoelectronic applications such as touchscreen, photovoltaic, and smart window devices. Excellent TCO's should exhibit high electrical conductivities, high carrier mobilities, and high transparency in the visible spectrum. Indium tin oxide (ITO), the most widely used TCO, combines all of these properties. However, the rising price of indium has significantly increased the cost of ITO-based devices. Thus, it has become necessary to seek effective TCO's that do not require the use of indium. We propose to look for new TCO's by using strong electron correlations introduced by electron doping of insulating d0-titanates through hydrogen plasma exposure (hydrogenation). Hydrogenation generates conductivity in an insulating oxide by introducing electron carriers, causing an insulator-to-metal transition. Our preliminary results on SrTiO3, Ba0.5Sr0.5TiO3, and BaTiO3 films show the onset of conductivity with good optical transparency via plasma hydrogenation. We will investigate poly-crystalline and amorphous thin-films to understand the mechanism of their insulator-to-metal transitions as well as to further improve their electric conductivities and optical transparency via plasma hydrogenation. The outcome of this project will provide important information about their potential applications as next-generation TCO devices.