Materials science and engineering. B: Solid-state materials for advanced technology vol:159-160 pages:286-290
To answer the challenge of less expensive renewable electricity, the photovoltaics community is focusing on producing thinner silicon solar cells. A few years ago, in the field of silicon-on-nothing structures, micron-thick monocrystalline layers suspended over their parent wafer were produced by high-temperature annealing of specific arrays of macropores. Those macropores reorganise into one single void and leave a thin overlayer on top. Since this method may be an inexpensive way of fabricating high-quality silicon films, this paper investigates its potential for photovoltaic applications. In particular, we investigated if large surfaces can be produced and transferred to foreign substrates with this method. We fabricated basic solar cells, without rear-surface passivation, on 5 cm x 5 cm-large and 1-mu m-thick films transferred to glass, that showed energy-conversion efficiencies up to 2.6%. These cells demonstrate the feasibility of the presented concept as a layer-transfer process for solar-cell application. After formation by annealing, the film is only barely attached to its parent wafer, but can still safely be handled provided that any abrupt gas flow or pumping to vacuum is avoided. After transfer and permanent bonding, the sample can be handled as any bulk wafer. (c) 2008 Elsevier B.V. All rights reserved.