We use low cost photolithography and low temperature chemical processes to fabricate highly sensitive nanowire gas sensing chips. With the combination of a small gas chamber, a mini fan, a UV light emitting diode, and a bluetooth circuit, a portable resistive gas sensing device is formed. The device is wirelessly connected to a smart phone via the bluetooth circuit. The resistance change of the sensing chip due to chemically active gas is recorded in an APP program and the gas concentration in the chamber or the surrounding environment can be detected.
  The sensing material is made of nanoparticle decorated ZnO nanowires. ZnO is an n-type semiconductor. When chemically active gas molecules adsorb on ZnO, the resistance of the sensing chip will change. With the decoration of p-type semiconductor nanoparticles, p-n junctions are formed on the surfaces and the sensitivity is greatly enhanced. So far, resistance changes of 350% at 1 ppm NO and 10% at 60 ppb NO have been obtained under ambient environment. It is expected that high responses will be achieved for other active gases, which is currently under investigation. The present gas sensing device can be potentially used for toxic gas alert, processing monitoring, air pollution detection, human exhaled breath detection, etc.

可攜式、低濃度(< 1 ppm)氣體測量、手機app程式操作介面

初期市場可能在製造業毒氣偵測預警、環境空汙偵測、呼氣酒精濃度測量