Planar rose-like ZnO/honeycombed gallium nitride heterojunction prepared by CVD towards enhanced H2 sensing without precious metal modification

Abstract In this work, through chemical vapor deposition (CVD) method, almost indistinguishable planar rose-like ZnO (PRZ) nanostructures could be prepared on the surface of honeycombed gallium nitride (HGaN) after more than ten deposition tests, and then constructed into PRZ/HGaN heterojunction gas sensor. Subsequent gas behaviors showed that the PRZ/HGaN heterostructure constructed by CVD greatly improved the selectivity and response value (32.5 at 100 ppm) to H2, and realized the improvement of the H2 sensing performance without noble metal modification. Importantly, fast response and recovery time was 47 s and 6 s, respectively. Meanwhile, this sensor presented excellent selectivity and stability. Ultimately, the dynamic monitoring of the sensor was performed for five consecutive months, and the fluctuation ratio of the response value (sensitivity) did not exceed ±2%. It could be predicted that the as-obtained sensor was expected to promote the substantial process of industrialization of highly stable metal oxide/HGaN heterojunction sensors.