Patent ID: 7631540

Claim:
A method for detecting the existence of NO x in a gas sample with a gas sensor, said gas sensor comprising: a substrate; two separated metal electrodes located on a surface of said substrate; a semiconductor film deposited on the surface of said substrate and connecting said two metal electrodes; wherein said semiconductor film comprises zinc oxide or a mixed oxide of zinc and indium, and said zinc oxide or said mixed oxide of zinc and indium are in the form of nanowires which constitute a gas-sensing surface of said semiconductor film, wherein said nanowires have a diameter of 5-900 nm and in a substantially perpendicular orientation to the surface of the substrate, said method comprising exposing said gas-sensing surface of the gas sensor to said gas sample; measuring an electric signal resulting from a variation in electric resistance between the two electrodes of said gas sensor; and comparing said electric signal with a preset value, and determining whether NO x exists in said gas sample based on a difference between the electric signal and the preset value, wherein x=1˜2.