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conferenceseries .com
Volume 4, Issue 4 (Suppl) J Laser Opt Photonics, an open access journal
ISSN: 2469-410X Optics 2017
November 15-17, 2017
November 15-17, 2017 | Las Vegas, USA
8th International Conference and Exhibition on
Lasers, Optics & Photonics
Laser power conversion efficiencies exceeding 60%, featuring strong photon recycling, in ultra-thin GaAs
n/p junctions based on high-photovoltage vertical epitaxial heterostructure architectures
Simon Fafard
Université de Sherbrooke, Canada
Optical to electrical power converting semiconductor devices are achieved with breakthrough performance using a Vertical
Epitaxial HeteroStructure Architecture (VEHSA design). The devices allow achieving a near-optimum responsivity, an improved
photovoltage output compared to p/n junctions with standard thicknesses and low series resistance and shunting effects yielding high
fill-factor values. The ultrahigh conversion efficiencies were obtained by monolithically integrating several thin GaAs photovoltaic
junctions tailored with submicron absorption thicknesses and grown in a single crystal by epitaxy. Unique experimental evidence of
the significant impact of photon recycling in these photovoltaic devices has been observed. The devices exhibited a near optimum
responsivity of up to 0.645A/W for tuned excitation conditions or at high optical intensities for spectral detuning values of up to ~25
nm and corresponding to an external quantum efficiency of ~94%. These devices have now available as products manufactured by
Broadcom and recent progresses will be covered, including: -The highest optical to electrical efficiency ever achieved; -The highest
output powers ever reported for a high-efficiency monolithic PV cell with 5.87W of converted output from a CW laser; -The highest
efficiencies ever reported for any types of optical to electrical power conversion devices simultaneously combining high photovoltage
and output powers (> 5W at > 7V with > 60% efficiency and > 3W at > 14V with > 60% efficiency); -The highest efficiency ever
reported of 61.8% with a significantly detuned optical input; -The highest photovoltage ever reported for monolithic photovoltaic
semiconductor heterostructures with measured Voc > 23V; The thinnest p/n junctions ever implemented successfully with high-
performance, with ultra-thin GaAs bases as small as 24 nm.
Biography
Simon Fafard was a Co-founder & President of Broadcom which is a large public company that recently acquired Azastra and has been an innovative Canadian opto-
electronic company. He has been focused on optoelectronic at uSherbrooke and at Azastra, a corporation that commercialized laser power converter products based on
the new VEHSA technology. He has an h-index of 45 and is the inventor of over 30 patents. He raised over $20M of private and venture capital funding and also obtained
numerous research grants. He led Cyrium to become a manufacturer of one of the highest performance multijunction III-V solar cells and led Azastra to manufacture the
highest performance phototransducer products. As an entrepreneur, he cumulates over 25 years of experience in Optoelectronics and Photonics while developing and com-
mercializing numerous devices and products in the industry at Azastra, Aton, Cyrium, Alcatel Optronics, Kymata and also in research labs at uSherbrooke, NRC and UCSB.
Simon Fafard, J Laser Opt Photonics 2017, 4:4 (Suppl)
DOI: 10.4172/2469-410X-C1-017