Carbon mon:oxide sensor with high sensitivity - uses semiconductor layers of doped stannic oxide, and platinum-gold layer

摘要

The sensor consists of an insulating substrate (a) coated with a layer (b) of SnO2, followed by a layer (d) of Pt+Au. At least one donor (b1) is pref. added to layer (b); or layer (b) includes a layer (b2) of SnO2 contg. a donor (b1) and is followed by a layer (c) of SnO2 contg. an acceptor (c1) and then layer (d). Layer (d) is pref. Pt with average thickness 0.3-30 atoms, contg. 0-50 atomic% Au. Two pairs (e, f) of contacts are pref. used for layers (a, b, c, d) where the distance (L2) between contacts (f) is larger than the distance (L1) between the tweo contacts (e). The resistance value of the sensor can easily be adjusted to trigger an alarm when the combustion of gases in a burner is incomplete so CO is formed; and the sensitivity of the detector is not affected by other gases such as NOx.