In order for nanowire based architectures to fulfill the demands of future technology, like for photovoltaics and light emitting diodes, there is a strong need for making available large area economically viable patterning of catalyst particles, defining the sites for nanowire growth. We use the IPS-STU nanoimprint process (http://www.obducat.com) for pattern definition and soft imprint, metal evaporation and lift off on 2” wafers for nanowire growth. The detailed process development with respect to each specific stamp and wafer type is developed in house. After imprint and growth, techniques to transfer as grown NWs from the substrate to a metal film and commercial Si PV are developed. PDMS is used to embed the nanowires and allow transfer of the nanowire containing plastic film to contacting material. The short length and thin diameters of the NWPV poses strong demands on processing in order to enable contacting after transfer.
Image: Transfer and contacting for flexible nanowire devices enabling substrate reuse. Schematics of rip off and stransfer for flexible multi junction NWPV. a) Tandem junction NWs embedded in polymer (PDMS), and b) peeled off and placed on contact material. The tandem junction NWPV with substrate cost diminished (can be re-used for growth). The PDMS is thinned down in order to deposit the TCO and the front contact. Image by Magnus Borgström.
Mårtensson, T., Carlberg, P., Borgström, M., Montelius, L., Seifert, W., & Samuelson, L. (2004). Nanowire arrays defined by nanoimprint lithography. Nano Letters, 4(4), 699-702, DOI: 10.1021/nl035100s
Wallentin, J., Anttu, N., Asoli, D., Huffman, M., Aberg, I., Magnusson, M. H., . . . Borgstrom, M. T. (2013). InP nanowire array solar cells achieving 13.8% efficiency by exceeding the ray optics limit. Science, 339(6123), 1057-1060, DOI: 10.1126/science.1230969
|Magnus T Borgström|
|Postdocs and PhD students|
Site responsible: Magnus T Borgström