Temperature driven p- to n-type transition of In2O3/NixOy nanocavity structure for H2 gas sensors

This research focused on the synthesis of In₂O₃/Ni_xO_y nanocomposites utilizing the conventional template method. The resulting gas sensor, designed for H₂ detection, demonstrates a sensing behavior that is dependent on temperature. Various characterization techniques were employed to analyze the synthesized In₂O₃/NiO composite materials. The results obtained from tests conducted at different temperatures reveal that the sensor maintains a stable n-type response for H₂ at temperatures exceeding 240°C, while exhibiting an atypical p-type response at lower temperatures. This transition in adsorption behavior enables the In₂O₃/Ni_xO_y composites to function as a dual-mode sensor capable of detecting H₂. The temperature-induced transformation is likely attributable to the interplay of several mechanisms. This article elucidates this phenomenon by examining factors such as activation energy, TGA/DSC, adsorbed oxygen, heterojunction formation, and humidity effects. This study contributes to the understanding of the transformation mechanisms underlying MOS gas sensing behavior.