A study on gas sensors using a SAW device

When an open type stove is used indoors, NO₂ is generated by the combustion of the fuel, which can lead to respiratory diseases or allergic reactions. In addition, SO₂ is also generated by the combustion of fossil fuels, which can cause asthma and bronchitis. In this paper, we propose a sensor, which uses a SAW device coated with Cu and Zn phthalocyanine films, for measuring the concentrations of NO₂ and SO₂. We have demonstrated that NO₂ and SO₂ concentrations in the 0.3-0.5 ppm range can be measured in a mixed gas containing a NO₂ and SO₂ by using sensors coated with 400 nm thick Cu phthalocyanine and 50 nm thick Zn phthalocyanine films, respectively. Furthermore, a multi sensor incorporating patterned Zn and Cu phthalocyanine films, capable of measuring the concentrations of both N0₂ and S0₂ has been demonstrated.