Chemical sensitive field effect transistors (CS-FET), which are conventional MOSFETs without gate electrodes will be fabricated and applied for low energy consumption, highly sensitive, small size, multi-gas detecting chemical sensors. The work functions of transition metal oxides (TMOs) deposited onto the channels of the CS-FETs can be manipulated by the adsorption of chemicals onto their surfaces. These changes cause a change in the surface potential of the underlying Si channel, leading to the current modulation of the devices. By selecting appropriate TMOs, different chemicals...