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.

European Research Council (ERC) , NWO
Elsevier B.V.
Nano Energy
3D Photovoltaics

Mikulik, D., Ricci, M., Tütüncüoglu, G., Matteini, F., Vukajlovic, J., Vulic, N., … Fontcuberta i Morral, A. (2017). Conductive-probe atomic force microscopy as a characterization tool for nanowire-based solar cells. Nano Energy, 41, 566–572. doi:10.1016/j.nanoen.2017.10.016