Sn:In2O3 and Sn:In2O3/NiS2 Core–Shell Nanowires on Ni, Mo Foils and C Fibers for H2 and O2 Generation

Abstract

Sn:In2O3 nanowires have been grown by the vapor liquid solid mechanism on Si, Ni, Mo, and C fibers. These were used to obtain Sn:In2O3/NiS2 core–shell nanowires by the deposition of 10 nm Ni over the Sn:In2O3 nanowires followed by post growth processing under H2S between 100 and 200 °C. The Sn:In2O3/NiS2 nanowires have diameters of ≈100 nm and lengths up to ≈100 μm and consist of cubic bixbyite Sn:In2O3 surrounded by 3 nm NiS2 crystalline quantum dots with a cubic crystal structure. Higher temperatures of 300–500 °C result in the formation of NiS2 quantum dots and cubic In3S4 branches around the Sn:In2O3. We find that the p-type NiS2 in contact with n-type Sn:In2O3 NWs gives rectifying current–voltage (IV) characteristics due to the formation of a p–n heterojunction with a straddling type band alignment where electrons are confined to the n-type Sn:In2O3 core and holes in the p-type NiS2, as shown by self-consistent Poisson–Schrodinger calculations in the effective mass approximation. The gas evolution of...