Mihaela Gorgoi, Dominic Gerlach, Regan G. Wilks, David Wippler, Manuel Wimmer, Mickaël Lozac'h, Roberto Felix Duarte, Leonie Anna Mück, M. Meier, Shigenori Ueda, Hideki Yoshikawa, Klaus Lips, Bernd Rech, Masatomo Sumiya, Jürgen Hüpkes, Kaoru Kobayashi, Marcus Bär
- The electronic structure of the interface between the boron-doped oxygenated amorphous silicon “window layer” (a-SiOx:H(B)) and aluminum-doped zinc oxide (ZnO:Al) was investigated using hard x-ray photoelectron spectroscopy and compared to that of the boron-doped microcrystalline silicon (μc-Si:H(B))/ZnO:Al interface. The corresponding valence band offsets have been determined to be (−2.87 ± 0.27) eV and (−3.37 ± 0.27) eV, respectively. A lower tunnel junction barrier height at the μc-Si:H(B)/ZnO:Al interface compared to that at the a-SiOx:H(B)/ZnO:Al interface is found and linked to the higher device performances in cells where a μc-Si:H(B) buffer between the a-Si:H p-i-n absorber stack and the ZnO:Al contact is employed.