Below Band-Gap IR Response of Substrate-Free GaAs Solar Cells Using Two-Photon Up-Conversion

概要

論文の詳細を見る
We have developed a device based upon the concept of two-photon up-conversion to use a part of the IR photons otherwise lost by transparency in a GaAs cell. An ultra thin GaAs cell has been fabricated using the technique of epitaxial lift-off (ELO). This thin cell is placed on top of a 100 μm thick vitroceramic doped with Yb^<3+> and Er^<3+>. The two photon upconversion process involved here is based on sequential absorption and energy transfer of two IR photons from Yb^<3+> to Er^<3+>, which then emit one photon in the green. This green light then produces a photoresponse in the GaAs cell. This cell coupled to the vitroceramic was lighted by an Ti-sapphire IR laser at 1.391 eV, a photon energy below the band gap of GaAs, with an input power able to reach 〜1W. The GaAs cell photoresponse increases quadratically with the input excitation. For an input excitation of 1W at 1.39 eV on a 0.039 cm^2 substrate-free GaAs cell, the measured efficiency was 2.5%.
社団法人応用物理学会の論文
1996-08-15