Gas-detecting apparatus including gas sensor and method of detecting hydrogen using gas sensor

A method of detecting gas with a gas sensor,

• the gas sensor comprising:
• an insulation film, and
• detection cells covered with the insulation film, wherein
• each of the detection cells includes:
• a first electrode;
• a second electrode having a surface exposed from the insulation film;
• and
• a metal oxide layer disposed between the first electrode and the second electrode, the mental oxide layer including a bulk area and a local area penetrating into the bulk area, a side face of the local area being surrounded by the bulk area, a degree of oxygen deficiency of the local area being higher than that of the bulk area, an upper surface of the local area and an upper surface of the bulk area being in direct contact with a bottom surface of the second electrode, a bottom of the local area being away from an upper surface of the first electrode, and
• the method of detecting gas comprising:
• monitoring resistance values of the detection cells;
• and
• deciding whether gas containing hydrogen atoms is detected or not based on at least one change in the resistance values.

A gas-detecting apparatus comprising:

• a measurement circuit including
• a gas sensor that includes an insulation film and detection cells covered with the insulation an insulation film, and
• at least one measurement instrument that monitors resistance values of the detection cells;
• and
• a decision circuit that decides whether gas containing hydrogen atoms is detected or not based on at least one change in the resistance values, wherein:
• the detection cells each include
• a first electrode,
• a second electrode having a surface exposed from the insulation film, and
• a first metal oxide layer, a bottom surface of the first metal oxide layer being in direct contact with an upper surface of the first electrode,
• a second metal oxide layer, an upper surface layer of the second metal oxide layer being in direct contact with a bottom surface of the second electrode, and
• a local area passing through the second metal oxide layer, an upper surface of the local area being in direct contact with the bottom surface of the second electrode, a bottom of the local area being away from the upper surface of the first electrode;
• a degree of oxygen deficiency of the first metal oxide layer is higher than that of the second metal oxide layer;
• a degree of oxygen deficiency of the local area is higher than that of the second metal oxide layer;
• and
• the resistance values of the detection cells are each allowed to decrease by a contact of the gas with the second electrode.