Aluminum-doped ZnO thin film gas sensor capable of detecting freshness of sea foods

Recently, the detection of freshness of foods has become an important routine in the fields of food industry such as food chemistry, food processing and food technology. It is, therefore, necessary to develop a rapid and non-destructive technique capable of detecting the freshness of sea foods, especially in the fish processing industry, since the widely used method of freshness detection of fish, based on the measurement of products of decomposition of adenosine triphosphate compounds in the tissue of the fish, requires a great deal of time and effort [l, 21. We have reported a gas sensor based on the electrical resistance change of sputtered zinc oxide (ZnO) thin films that exhibited a higb sensitivity and excellent selectivity for trimethylamine (‘IMA) gas [3]. The sensor responded to freshness of sea foods such as salmon, oyster, squid, sardine and sea bream [3, 41. It was found that the sensitivity of the sensor for TMA as well as to the odor from sea foods is improved by doping of aluminum (Al) impurity into the ZnO thin film. The object of tbii work is to investigate the dependence of the content of Al impurity doped in the ZnO (ZnO:Al) thin film gas sensor on the sensing characteristics for odor from sea foods.