Operating temperature and ruthenium doping influence on the charge carriers type transition in the ɑ-Fe2O3 sensors upon liquefied petroleum gases detection

Abstract

Metal oxide-based sensors have been extensively used for environmental monitoring, health, and safety. This work focuses on synthesizing ɑ-Fe2O3 and doping it with Ruthenium (Ru) to study its gas-sensing properties over flammable and hazardous gases. An anomalous behavior was observed during the Liquefied Petroleum Gas (LPG). This Ru-doped ɑ-Fe2O3 showed a charge carrier switching transition from n- to p-type conductivity due to Ru doping and the sensor’s operating temperature. The switching behavior on the Ru-doped samples happened between 3,000 and 4,000 ppm of the LPG concentrations. However, the Ru doping content did not seem to be affecting this transition except to alter the LPG response. The sensors’ operating temperature did alter the switching transition from n- to p-type conductivity. The temperatures varied from 175 to 225 °C. Metal Oxide Semiconductor (MOS) based on α -Fe2O3 nanoparticle doped with ruthenium (Ru- α-Fe2O3) was more selective towards LPG with a gas response of 24.41.