Gas Sensor and Manufacturing Method Thereof

Abstract

A gas sensor and manufacturing method thereof. The gas sensor includes a substrate, a pair of electrodes disposed on the substrate, and a gas sensing thin film covering the electrodes, the gas sensing thin film is made up of carbon nanotubes and tin oxide.

1 . A gas sensor, comprising:
 a substrate;   a pair of electrodes on the substrate; and   a gas sensing thin film covering the electrodes;   wherein the gas sensing thin layer comprises a mixture of carbon nanotubes and SnOx, wherein x=1-2, and the ratio of the carbon nanotubes to the SnOx is 0.001:100˜5:100 by weight.   
     
     
         2 . The gas sensor as claimed in  claim 1 , wherein the substrate is insulating material or semiconductor material. 
     
     
         3 . The gas sensor as claimed in  claim 2 , wherein the substrate is ceramic material. 
     
     
         4 . The gas sensor as claimed in  claim 3 , wherein the ceramic material is glass, aluminum oxide, silicon oxide, quartz, or mica. 
     
     
         5 . The gas sensor as claimed in  claim 2 , wherein the semiconductor material is silicon. 
     
     
         6 . The gas sensor as claimed in  claim 1 , wherein the electrodes are respectively gold, platinum, or silver. 
     
     
         7 . The gas sensor as claimed in  claim 1 , wherein the carbon nanotubes are single-walled carbon nanotubes (SWCNTs). 
     
     
         8 . The gas sensor as claimed in  claim 1 , wherein the are multi-walled carbon nanotubes (MWCNTs). 
     
     
         9 . The gas sensor as claimed in  claim 1 , wherein the ratio of the carbon nanotubes to the SnOx is 0.001:100˜0.05:100 by weight. 
     
     
         10 . The gas sensor as claimed in  claim 1 , wherein the electrodes respectively have a comb, strip, or helix shapes. 
     
     
         11 . The gas sensor as claimed in  claim 1 , further comprising an Ag/Pd layer on the end of the electrode. 
     
     
         12 . The gas sensor as claimed in  claim 11 , further comprising a pair of signal lines separately connected to the electrodes by the Ag/Pd layer to transfer a signal.