Fabrication of nanocubic ZnO/SnO2 film-based humidity sensor with high sensitivity by ultrasonic-assisted solution growth method at different Zn:Sn precursor ratios

Abstract

We fabricated humidity sensor using nanocubic ZnO/SnO2 prepared via sol–gel and immersion method deposited on sputtered ZnO-film-coated glass substrate. These combination methods were used to grow nanocubic structured ZnO/SnO2 at different molar ratios Zn:Sn for the first time. The experiment was conducted at difference molar ratio of Zn:Sn by varying the molar of Zn. The size of the cube reduces as the Zn molar increase. The luminescence of nanocubic structured ZnO/SnO2 was indicated around 400 and 600 nm corresponding to the ultra-violet (UV) emission and visible emission, respectively. The composition of molar ratio 10:10 of nanocubic structured ZnO/SnO2 gives the best sensitivity of 104 times for humidity sensor properties. Nanocubic structured ZnO/SnO2 have a great potential for humidity sensor application with high response (411 s) and recovery times (98 s), repeatability and good in stability.