Pulsed laser deposition of In₂O₃-SnO₂: from films to nano-wires

Metal oxides have been identified as promising materials many devices, such as lithium ion batteries and UV lasers. Furthermore, metal-oxide NWs have been embedded in field-effect transistors, lasers, solar cells, and various chemical sensors. Pulsed-laser deposition (PLD) has emerged as a promising approach for the fabrication of tin-doped indium oxide (ITO), with film or NW growth determined by the choice of a reactive (O₂) or inert (N₂) atmosphere. However, a mechanistic understanding of the influence of growth parameters on the morphology, composition, and crystal structure of the deposited film is needed. Additionally, PLD of various In₂O₃-SnO₂ mixtures has yet to be considered. We report on PLD of various In₂O₃ -SnO₂ mixtures on sapphire substrates. Using an inert atmosphere, we have identified parameters to obtain pyramid-shaped nano-scale clusters; tapered nano-rods; and high density, vertically oriented NWs. We explain the influence of deposition pressure on the growth mode transition from straight NW to tapered NW to pyramidal nano-clusters. Additionally, we examine the influence of deposition pressure and NW diameter on the NW resistivity, obtained via single-NW IV characteristics measurements.