Nitrogen Atmospheric-Pressure-Plasma-Jet Induced Oxidation of SnOx Thin Films

Abstract

SnOx thin films that were rf-sputter-deposited under various gas flow ratios ([O2]/([O2]?+?[Ar]) OFR?=?3.0, 3.6, 4.2 and 4.8?%) were rapidly annealed using atmospheric pressure plasma jets (APPJs) in temperature range of ~350¡V386?¢XC for up to 5?min. The original electron probe micro-analysis [O] contents in the as-deposited films were ~25, ~30, ~35 and ~40?% for films deposited at ([O2]/([O2]?+?[Ar]) gas flow ratios OFR?=?3.0, 3.6, 4.2 and 4.8?%, respectively. APPJ annealing increased the [O] content to ~35?% for films deposited at OFR?=?3.0 and 3.6?%, where the [O] content remained in similar levels for films deposited at OFR?=?4.2 and 4.8?%. Crystalline metallic Sn was identified in films as-deposited at OFR?=?3.0 and 3.6?%; on the other hand, an X-ray amorphous SnOx phase was identified in films as-deposited at OFR?=?4.2 and 4.8?%. Crystallization and oxidation by APPJ annealing improved the transmittance and blue-shifted the absorption band edge to ~420?nm. All APPJ-annealed films exhibit n-type conductivity that may be contributed by the mixed phases of SnO, SnO2 and a small amount of Sn. ? 2015, Springer Science+Business Media New York.