▎ 摘　　要

NOVELTY - The logic device has light valve layer which is equipped with graphene layer (26). The light valve layer is in opposite direction to the gate electrode of the graphene transistor. The light valve layer is formed on the graphene layer. The light-transmissive gate electrode logic device is formed on the phase-change layer (32). USE - Logic device e.g. exclusive OR. ADVANTAGE - Different logical actions can be performed according to the switching on and off of the light. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) an operation method of the logic device; and (2) a manufacturing method of the logic device. DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of the logic device. Substrate (20) Gate electrode (22) Insulating layer (24) Graphene layer (26) Phase-change layer (32)