We investigated the electrical properties of the Cu(In,Ga)Se-2/MoSe2/Mo str
ucture. CIGS/Mo heterocontact including the MoSe2 layer is not Schottky-typ
e but a favorable ohmic-type contact by the evaluation of dark I-V measurem
ent at low temperature. A characteristic peak at 870 nm is observed in diff
erential quantum efficiency of a solar cell with a CIGS thickness of 0.5 mu
m. This peak is considered with relating to the absorption of the MoSe2 lay
er. The band gap of MoSe2 is calculated to be 1.41eV from the absorption pe
ak. The band diagram is discussed on the basis of the electrical point of v
iew. (C) 2001 Elsevier Science B.V. All rights reserved.