Characterization of silicon heterojunctions for solar cells
1 Laboratoire de Génie Electrique de Paris, CNRS UMR 8507, SUPELEC, Univ P-Sud, UPMC Univ Paris 6, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette Cedex, France
2 A.F. Ioffe Physico-Technical Institute, Polytechnicheskaya Str. 26, St. Petersburg, 194021, Russia
3 St. Petersburg Academic University-Nanotechnology Research and Education Centre RAS, Hlopina Str. 8/3, St. Petersburg, 194021, Russia
4 Laboratoire de Physique des Interfaces et des Couches Minces, Ecole Polytechnique, CNRS, 91128 Palaiseau, France
5 TOTAL S.A., Gas & Power-R&D Division, Courbevoie, France
Nanoscale Research Letters 2011, 6:152 doi:10.1186/1556-276X-6-152Published: 16 February 2011
Conductive-probe atomic force microscopy (CP-AFM) measurements reveal the existence of a conductive channel at the interface between p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) as well as at the interface between n-type a-Si:H and p-type c-Si. This is in good agreement with planar conductance measurements that show a large interface conductance. It is demonstrated that these features are related to the existence of a strong inversion layer of holes at the c-Si surface of (p) a-Si:H/(n) c-Si structures, and to a strong inversion layer of electrons at the c-Si surface of (n) a-Si:H/(p) c-Si heterojunctions. These are intimately related to the band offsets, which allows us to determine these parameters with good precision.