Effect of growth duration to the electrical properties of Zn doped SnO2 thin film toward humidity sensor application

This technical paper investigates the electrical properties of the Zinc doped SnO₂ (Zn-doped SnO₂) nanostructures that have been prepared by the immersion method by different period of immersion process. The experiment was conducted in 3 different time constraint. The thin films were characterized by using current-voltage (I-V) measurement (Keithley 2400). The results analyzed were for time duration of 6, 12 and 24 hour. At initial stage, the substrate which is a glass was deposited by ZnO using RF magnetron sputtering method. Zn has been doped by SnO₂ using immersion process. The optical and structural properties has been characterized using photoluminescence (PL) measurement (Horiba Jobin Yvon-DU420A-OE-325 system) and field emmision scanning electron microscopy (FESEM) (JEOL JSM 6701F) respectively. The sensor were characterized using I-V measurement (Keithley 2400) in a humidity chamber (ESPEC SH-261) and the chamber has been set at same room temperature (25°C) but different percent relative humidity (RH %) at 40 RH% to 90 RH. The highest sensitivity was resulted at 24 hours immersion process. PL measurement revealed one peak at about between range red emission for all Zn-doped SnO₂ thin film while for ZnO catalyst reveal two peaks at UV region (380 nm) and visible range (600 nm). FESEM image show the possible growth of nanoparticle and nanocube Zn-doped SnO₂ growth on the nucleation site of ZnO catalyst.