A quantum device is constituted from a two-dimensional array of quantum dots
formed
from metal atom aggregates contained in a metalloprotein complex. The metalloprotein
is arranged on the surface of a substrate having an insulation layer with a pitch
of the size of the metalloprotein complex. The diameter of the metal atom aggregates
used in the quantum device is 7 nm or smaller, and the pitch of the metalloprotein
complex is preferably from 11 to 14 nm.