Doping dependent NH3 sensing of indium oxide nanowires

Abstract

${\mathrm{NH}}_3$ gas sensing properties of ${\mathrm{In}}_2{\mathrm{O}}_3$ nanowires were carefully studied. Change of conductance in opposite directions was observed with different nanowire sensors. We suggest that this differential response is caused by various doping concentrations in the semiconducting ${\mathrm{In}}_2{\mathrm{O}}_3$ nanowires. In addition, we have also investigated a “gate-screening effect” exhibited in our nanowire chemical sensors at high ${\mathrm{NH}}_3$ concentrations, which is induced by adsorbed ${\mathrm{NH}}_3$ molecules working as charge traps. Both the doping-dependent response and the gate-screening effect will be especially valuable and helpful for understanding the detailed sensing mechanism of semiconducting metal oxide materials.