Single-electron transistor (SET) which operates as capacitively-coupled SET
(C-SET) and resistively-coupled SET (R-SET) was fabricated using two-dimen
sional electron gas and metal Schottky gates. The Coulomb di amends of both
C-SET and R-SET were observed at similar or equal to 30 mK. The observed C
oulomb diamond of R-SET is shifted along the gate-voltage axis, although it
should not be shifted in the theoretical prediction.