Abstract <p>The enhancement of volatile organic compound (VOC) sensitivity utilizing a single metal oxide sensing element at room temperature with low power consumption offers substantial technical challenges. Heterojunctions of metal oxides can overcome the limitations of a single metal oxide thin film such as poor gas sensitivity and selectivity. The present work investigates the sensing ability of ZnO/Cu₂O heterojunction thin films towards acetone detection near room temperature. Direct-current (DC) magnetron sputtering and thermal evaporation techniques are used to synthesize ZnO/Cu₂O thin films, where ZnO is grown on a Cu₂O layer. Investigations of the surface morphology, elemental composition, crystal structure, and electrical properties are performed to determine its dependence on the physically observable parameters and to reveal the deep sensing mechanism. ZnO/Cu₂O exhibits a considerable change in resistivity upon acetone exposure, particularly at lower temperatures (30–90°C). The investigation of the response and recovery time of the sensing element under acetone vapor exposure up to 4.5&#xa0;min is addressed in this work. Their gas-sensing behavior changes from n-type to p-type with the increase in the growth temperature. This work presents a promising application of ZnO/Cu₂O heterojunction thin film for acetone sensor technology.</p> Graphical Abstract <p></p>