NO and NO_2 gas sensors based on surface photovoltage system fabricated by self-ordered mesoporous silicate film

摘要

The first NO and NO_2 gas sensors based on surface photo-voltage (SPV) semiconductor device system are fabricated by the metal/ SiO_2 (self-ordered hexagonal mesoporous)-/Si_3N_4/SiO_2/Si structure. Size controlled silicate hexagonal mesoporous film is successfully synthesized by spin coating on a Si_3N_4SiO_2Si silicon wafer using poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) (Pluronic P123 =EO_(20)PO_(70)EO_(20)) triblock copolymers as a template. The characteristics of mesoporous film are investigated in XRD, TEM. The sensing properties of the self-ordered hexagonal mesoporous SPV system have been investigated by exposing to the NO or NO_2 gas and air repeatedly. The changes of the average value and phase of the AC photocurrent (I_(ph)) have been observed between the NO or NO_2 gas and air. The response of the alternatively photocurrent is resulted from the physical adsorption and chemical interaction between detected NO or NO_2 gas and the self-ordered hexagonal mesoporous film.