ZnO nanostructures growth by hydrothermal process for nitrate ion sensing application

ZnO nanostructures were grown on glass substrate using a hydrothermal process with zinc nitrate hexahydrate and hexamethylenetetramine ratio of 1:1. In this work, the growth of ZnO nanostructures is executed at oven temperature of 95°C for 5 hours. The XRD results demonstrate the presence of ZnO on the growth sample with the highest peak corresponding to planes at (100), (101), and (002) appeared at ~31.7°, ~34.4° and ~36.2° respectively. The VPSEM image shows random arrangement of nanostructures. The sample has a resistivity of ~1.23 MΩ with nitrate ion sensitivity range of 39.29 to 57.75. This sample was used to test with 1M of nitrate solution to study the sensing properties. Repetitive measurements at 1.5V after exposed with nitrate solution shows a minimum current drift of 4.27% for the first two measurement and maximum drift at fifth measurement of 36.75%. This indicates a reliable result can be obtained in the first two measurements with nitrate solution.