Magnetic Ni/n-Si Schottky Contact as Hydrogen Gas Sensor

In this paper the sensing characteristics of magnetic and non-magnetic Ni/n-Si contacts as hydrogen gas sensors are discussed. The Ni/n-Si Schottky contacts were prepared using electron beam evaporation of ferromagnetic Ni films with thickness of 50 nm onto n-type Si substrates. To improve gas sensitivity, an appropriate profile to magnetize the ferromagnetic Ni contact has been used. From forward current-voltage characteristics we have found that the magnetic Ni/n-Si contact exhibited much more sensitivity than the non-magnetic Ni/n-Si sensor in response to different concentrations of hydrogen gas. Moreover, the responsivity of the magnetic Ni/n-Si sensor was investigated towards hydrogen gas at various operating temperatures between 25degC and 230degC. An explanation has been proposed to explain how the magnetization of Ni can affect sensitivity significantly.