▎ 摘　　要

NOVELTY - The sensor (10) has a semiconductor layer (101) arranged in a first detection part (100) or a second detection part (200), where electrical property of the first detection part is changed according to concentration of first gas of a detection chamber (11), and electrical property of the second detection part is changed according to concentration of second gas of the detection chamber. A graphene film (111) is provided in the semiconductor layer along an upper direction. A barrier film (104) is arranged between the semiconductor layer and the graphene film. A first electrode (105g) is arranged with the graphene film. A second electrode (105s) and a third electrode (105d) are provided in a surface of the semiconductor layer as a downward part of the barrier film is interposed between the second and third electrodes. USE - Gas sensor for use in a gas detection system (claimed) for detecting chemical substance in gas i.e. nitrogen monoxide, to point out correlation of stomach cancer and concentration of ammonia in expired-air, and correlation of asthma and concentration of gas in expired-air. ADVANTAGE - The sensor utilizes the detection parts to detect the gas by high sensitivity. DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a gas sensor. '(Drawing includes non-English language text)' Gas sensor (10) Detection chamber (11) Detection parts (100, 200) Semiconductor layer (101) Barrier film (104) Electrodes (105d, 105g, 105s) Graphene film (111)