▎ 摘　　要

NOVELTY - The sensor (100) has a dielectric film (104) formed between a channel semiconductor region (101) and a graphene film (105). The channel semiconductor region is formed between a source semiconductor region (102) and a drain semiconductor region (103). The graphene film is formed in the channel semiconductor region along upper direction, where movement of a carrier from the source semiconductor region to the channel semiconductor region is increased by tunnel effect between bands. The source semiconductor region is formed with a bulk semiconductor. USE - Gas sensor for a medical device and a diagnostic apparatus for detecting gas i.e. ammonia, during diagnosis of stomach cancer. ADVANTAGE - The graphene film is formed in the channel semiconductor region along the upper direction, where the movement of the carrier from the source semiconductor region to the channel semiconductor region is increased by the tunnel effect between the bands, so that gas such as ammonia can be detected with high sensitivity. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a gas sensor usage method. DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a gas sensor. '(Drawing includes non-English language text)' Gas sensor (100) Channel semiconductor region (101) Source semiconductor region (102) Drain semiconductor region (103) Dielectric film (104) Graphene film (105)