Multi arrays ZnO Thin Film Gas Sensor

Multi arrays system of ZnO gas sensor has been fabricated using DC sputtering technique. The objective at the arrays system is to simplify the system, to minimize the power consumption and to make small the resistance of the formed thin layer. For the purpose, the filament system has been made from thin layer gold in multi arrays system from deposited on back side of alumina (Al2O3) substrate, while the electrodes system are also made from thin layer gold in multi arrays system form deposited on front side of alumina (Al2O3) substrate. Then the ZnO thin layer deposited on electrodes system. From characterization done, it has been found that the working temperature in order of 295 oC was achieved by applied of battery power 4.5 volt, while for heater voltage 9 Volt, the thin layer heater initiate to peel off. From responses testing done for various gas tested, it has been found that in multi arrays layer system, the higher the layer, the smaller the resistance of the system. For example, the resistance of mono layer ZnO thin film is 150 MΩ, while the resistance for three layers is 39 MΩ. It was also found that the sensitivity of higher layer ZnO thin film more sensitive. From microstructure analysis using SEM, it's found that the grains were distributed homogeneously on glass substrate and the thickness of the layer is in order of 1.4 μm. From chemical composition analysis using EDX, it's found that the formed layer is really compound with composition of Zn 80.34 % mass and O = 19.66 % mass. From structure crystal analysis using XRD, it's observed that the thin layer was polycrystal with the cristal plane (110), (022), (101), (141), (211), (002) and (301). (author)