Conductive-probe atomic force microscopy as a characterization tool for nanowire-based solar cells

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DOI http://dx.doi.org/10.1016/j.nanoen.2017.10.016
Reference D. Mikulik, M. Ricci, G. Tütüncüoglu, F. Matteini, J. Vukajlovic, N. Vulic, E. Alarcón-Lladó and A. Fontcuberta i Morral, Conductive-probe atomic force microscopy as a characterization tool for nanowire-based solar cells, Nano Energy 41, 566-572 (2017)
Group 3D Photovoltaics

The photonic properties of nanowires advocate for their utilization in next generation solar cells. Compared to traditional devices, the electric scheme is transformed from a single into an ensemble of pn junctions connected in parallel. This new configuration requires new schemes for the characterization. We show how conductive-probe atomic force microscopy, C-AFM, is an essential tool for the characterization and optimization of this parallel-connected nanowire devices. With C-AFM it is possible to obtain both surface topography and local electrical characterization with nanoscale resolution. We demonstrate topography and current mapping of nanowire forests, combined with current-voltage measurements of the individual nanowire juncitions from the ensemble. Our results provide discussion elements on some factors limiting the performance of a nanowire-based solar cell and thereby to provide a path for their improvement.