Al-doped ZnO/WO₃ heterostructure films prepared by magnetron sputtering for isopropanol sensors

Metal oxide semiconductors (MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to develop the MOSs-based gas sensors for sensing isopropanol with desired performance via a simple, effective, and controllable method. Herein, we reported the preparation of the Al-doped ZnO (AZO)/WO3 heterostructure films by directly depositing the AZO coating onto the WO3 coating using a strategy of magnetron sputtering. The AZO/WO3 heterostructure films were constructed by numbers of irregular nanoparticles that were interconnected with each other. The AZO/WO3 heterostructure films-based gas sensors exhibited excellent isopropanol-sensing performance with high response, promising selectivity, low detection limit, fast response rate, wide detection range, and ideal reproducibility. The promising isopropanol-sensing performance of the AZO/WO3 heterostructure films arises mainly from their high uniformity, unique microstructures with high surface roughness, and the construction of the heterostructure between the AZO and WO3 coatings. This work provides a versatile approach to prepare the MOSs-based heterostructure films for assembling the gas sensors.