Highly sensitive low power metal oxide sensors on nanoporous anodic alumina substrates

Abstract

The high physical, chemical, and mechanical properties of anodic alumina open up broad prospects for its use as a passive substrate for gas sensors. The results of practical tests of low-power thin-film gas microsensors manufactured on nanoporous anodic alumina substrates are presented. Due to the original design and the nanostructured gas-sensitive layers (GSLs), the sensors had low power consumption and a high sensitivity to 10 ppm H2 and 10 ppm CO. Comparative studies of gas sensor responses were carried out with three GSLs of In2O3–Ga2O3; SnO2–Pd and In2O3–SnO2 at different operating temperatures. All sensors demonstrated high performance; in particular, the energy consumption during measurements did not exceed 30–40 mW, the maximum sensitivity for CO reached 350%, and for H2 up to 140%, the response time was no more than 10–15 s, and the regeneration time—no longer than 20–25 s, high measurement reproducibility and operation stability, the drift of GSLs was 3%–5% over several months. With proper organization of production, such sensors are capable of competing with many advanced analogs.