The present invention provides a method for production of a single
electron semiconductor element (SET) in which a quantum dot is
selectively arranged in a nano gap between fine electrodes, whereby the
product yield is significantly improved, leading to excellent practical
applicability. The method for production of SET of the present invention
is characterized in that a solution containing ferritin including a metal
or semiconductor particle therein, and a nonionic surfactant is dropped
on a substrate having a source electrode and a drain electrode formed by
laminating a titanium film and a film of a metal other than titanium,
whereby the ferritin is selectively arranged in a nano gap between the
source electrode/drain electrode.