▎ 摘　　要

NOVELTY - An apparatus (1) comprises graphene field effect transistor (3) which consists of graphene channel (5) and quantum dots (7) provided overlaying graphene channel in which quantum dots contain 1st layer (9) having quantum dots connected to 1st ligand (11) and 2nd layer (13) having quantum dots connected to 2nd ligand (15), 1st ligand is configured to cause 1st layer to have 1st refractive index and 2nd ligand is configured to cause 2nd layer to have 2nd refractive index that is different to 1st refractive index. USE - An apparatus for photodetector (claimed). ADVANTAGE - Overall thickness of apparatus is minimized. Proportion of light that reaches quantum dots is increased. Photodetector is improved. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) photodetector; and (2) formation of apparatus (1). DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the apparatus. Apparatus (1) Graphene field effect transistor (3) Graphene channel (5) Quantum dots (7) 1st layer (9) 1st ligand (11) 2nd layer (13) 2nd ligand (15)