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Low-Energy Generation in a Silicon Metamaterial: Some Ways for Utilization in Ultrahigh Efficiency Solar Cells
Z.T. Kuznicki, P. Meyrueis
Advanced Photovoltaics
Subtopic: Fundamental Studies
Event: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session: 1AO.4.6
49 - 53
ISBN: 3-936338-24-8
Paper DOI: 10.4229/23rdEUPVSEC2008-1AO.4.6
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Document(s): paper


Generation of more than one free-carrier depends on a multistage nonlinear process and requires special dedicated low-energy centers. A cascade-like progression induced by an interband absorption allows a Si metamaterial to convert 400 nm photons into collectable primary and secondary free-carriers [1]. Such carriers can be drawn into the external electrical circuit even in a multiinterface architecture containing a carrier collection limit. (CCL). This conversion performance is inversely proportional to incident light intensity. We have conceived and fabricated Si test structures containing a Si metamaterial by an amorphizing dose ionimplantation and suitable thermal treatment. The photoluminescence investigations of samples totally amorphized at the surface zone and with two states of the front face (passivated and bare) has allowed a clear visualization of specific nonradiative recombination mechanisms at the origin of the low-energy secondary generation. An optimization of the effect by suitable conditioning and annealing should be possible, opening the way to different applications, especially in the areas of nanophotovoltaics and ultrahigh efficiency solar cells.