Indium-implantation-induced enhancement of gas sensing behaviors of SnO2 nanowires by the formation of homo-core-shell structure

We present a new sensing mechanism concept to explain the enhanced gas response of In-implanted SnO2 nanowires (NWs) obtained by ion implantation. We first prepared SnO2 NWs and then implanted indium ions on SnO2 NWs at doses of 2 x 10(14) and 1.8 x 10(15) ion/cm(2), respectively. Gas sensors were fabricated, and the gas sensing properties of pristine and In-implanted SnO2-NW-based gas sensors were investigated. The sensing results demonstrated that the implanted In3+ improved the gas sensing performance. The obtained results indicated that the sensing improvement of the In-implanted (2 x 10(14) ion/cm(2)) SnO2 NW gas sensor was associated with the formation of structural defects and, most importantly, generation of a homo-core-shell structure within the SnO2 NWs. This structure acted as a powerful source of resistance modulation and significantly improved the response of the optimized gas sensor. Therefore, we demonstrated the possibility of sensing enhancement of metal oxides by ion implantation.