Characterization of heterojunctions in crystalline-silicon-based solar cells by internal photoemission

Isao Sakata , Mitsuyuki Yamanaka, Hitoshi Kawanami
Research Center for Photovoltaics,National Institute of Advanced Industrial Science and Technology (AIST),1-1-1Umezono, AIST Central-2, Tsukuba, Ibaraki305-8568,Japan
a r t i c l e info
Article history:
Received20December2007
Accepted16September2008
Availableonline5November2008
Keywords:
Internal photoemission
Heterojunction
Band discontinuity
Crystalline-silicon-basedsolarcells
a b s t r a c t
Internal photoemission(IPE)has been successfully applied to evaluate band offsets of heterojunctions
(HJs) incrystalline silicon (c-Si)-based solar cells.Tunneling of carriers through the potential spike at HJ
and the presence of a carrier conduction path in the wide-band-gap material of HJ can affect the IPE
results. In other words, IPE measures the effective band discontinuity, including effects of the carrier
conduction path. This feature of IPE is suited for the characterization of solar-cell structures. Results
obtained for hydrogenated amorphous silicon/c-Si HJ and gallium phosphide/c-Si HJ are presented and
discussed.
& 2008ElsevierB.V.Allrightsreserved.

Characterization of heterojunctions in crystalline-silicon-.pdf