A potentiometric oxygen sensor based on LaF3 using Pt micro grid as the sensing electrode

A solid-state gas sensor with the structure of Pt micro grid (sensing electrode)/ LaF3 (solid electrolyte)/ Sn, SnF2 (reference electrode) was developed for detecting oxygen at room temperature. In the oxygen sensor, Pt micro grid with the thickness of 60nm was fabricated on one side of the solid electrolyte (LaF3) wafer by lift-off process, which was used as a novel structure of sensing electrode for the purpose of changing the diffusion process of gas species and investigating the relationship between the sensing electrode dimensions and properties of the sensor. In order to form SnF2 layer on the other side of the LaF3 wafer, Sn film about 2µm thick was deposited on LaF3 wafer using sputtering technique first. Then the sensor cell was electrolysed at 0.2µA for 6 min in air at room temperature. The sensing mechanism was investigated in detail and it was found that the electromotive force(EMF) of the sensor depends on the partial pressure of O2. The sensing properties of the sensor were also tested.

[1]  N. Yamazoe,et al.  MOS-Type Micro-Oxygen Sensor Using LaF3 Workable at Room Temperature , 1990 .

[2]  N. Yamazoe,et al.  Solid-state oxygen sensor using sputtered LaF3 film , 1989 .

[3]  N. Yamazoe,et al.  Potentiometric solid-state oxygen sensor using lanthanum fluoride operative at room temperature☆ , 1987 .

[4]  S. Vilminot,et al.  Characteristics of an oxygen gauge at temperatures lower than 200°C , 1983 .

[5]  N. Yamazoe,et al.  A POTENTIOMETRIC OXYGEN SENSOR USING LaF3 SINGLE CRYSTAL OPERATIVE AT ROOM TEMPERATURE , 1984 .

[6]  S. Krause,et al.  Improved long-term stability for an LaF3 based oxygen sensor☆ , 1994 .

[7]  A. Ismail,et al.  Influence of deposition rate of LaF3 and annealing on the capacitance–voltage (C–V) characteristics of LaF3/Si heterostructures , 2009 .

[8]  W. Unger,et al.  Influence of the LaF3/metal interface on the properties of a low temperature oxygen sensor , 1993 .

[9]  H. Wiemhöfer.  Electronic properties and gas interaction of LaF3 and ZrO2 , 1990 .

[10]  John Crank,et al.  The Mathematics Of Diffusion , 1956 .

[11]  N. Yamazoe,et al.  Solid electrolyte oxygen sensor using LaF3 sputtered film workable at room temperature. , 1987 .

[12]  C. O. Tiller,et al.  A Solid‐State Electrode for Reducible Gases , 1973 .

[13]  N. Yamazoe,et al.  A LaF3-based oxygen sensor with perovskite-type oxide electrode operative at room temperature , 1990 .

[14]  B. Cho,et al.  Characteristics of a thin-film LaF3 solid electrolyte for oxygen sensing , 1991 .

[15]  P. Fabry,et al.  Utilization of a dilute solid electrolyte in an oxygen gauge , 1980 .

[16]  N. Yamazoe,et al.  LaF3 sputtered film sensor for detecting oxygen at room temperature , 1988 .

[17]  Re-activation of an all solid state oxygen sensor , 2001 .