Single step synthesis of highly conductive room-temperature stable cation-substituted mayenite electride target and thin film

Abstract

Novel approaches to synthesize efficient inorganic electride [Ca₂₄Al₂₈O₆₄]⁴⁺(e^-)₄ (thereafter, C12A7:e^-) at ambient pressure under nitrogen atmosphere, are actively sought out to reduce the cost of massive formation of nanosized powder as well as compact large size target production. It led to a new era in low cost industrial applications of this abundant material as Transparent Conducting Oxides (TCOs) and as a catalyst. Therefore, the present study about C12A7:e^- electride is directed towards challenges of cation doping in C12A7:e^- to enhance the conductivity and form target to deposit thin film. Our investigation for cation doping on structural and electrical properties of Sn- and Si-doped C12A7:e^- (Si-C12A7:e, and Sn-C12A7:e^-) reduced graphene oxide (rGO) composite shows the maximum achieved conductivities of 5.79 S·cm^-1 and 1.75 S·cm^-1 respectively. On the other hand when both samples melted, then rGO free Sn-C12A7:e^- and Si-C12A7:e^- were obtained, with conductivities ~280 S.cm^-1 and 300 S·cm^-1, respectively. Iodometry based measured electron concentration of rGO free Sn-C12A7:e^- and Si-C12A7:e^-, 3 inch electride targets were ~2.22 × 10²¹ cm^-3, with relative 97 ± 0.5% density, and ~2.23 × 10²¹ cm^-3 with relative 99 ± 0.5% density, respectively. Theoretical conductivity was already reported excluding any associated experimental support. Hence the above results manifested feasibility of this sol-gel method for different elements doping to further boost up the electrical properties.