Strain-Compensated GaAsN/InGaAs Superlattice Structure Solar Cells

概要

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In this work, we investigate the metal organic chemical vapor deposition (MOCVD) growth of GaAsN/InGaAs strain-compensated superlattice cells in view of their application in solar cells. The compressive strain in InGaAs layers is matched by the tensile strain in GaAsN layers, overcoming the lattice-mismatch limitation. GaAsN/InGaAs strained layer superlattice cells, lattice-matched to GaAs, are proposed to extend the long-wavelength absorption of the bottom cell in a cascade solar cell structure. A strain-compensated superlattice solar cell with 0.6 μm GaAsN/InGaAs incorporated in the intrinsic region of p–i–n GaAs cells was fabricated. Compared with the fabricated InGaAs and InGaNAs cells, it was found that the GaAsN/InGaAs superlattice cell can lower the band gap energy and extend the absorption the most, followed by the InGaAs cell. In addition, the efficiency of the GaAsN/InGaAs superlattice cell was 4.3%, which is comparable to that of the InGaNAs cell. The GaAsN/InGaAs strain-compensated superlattice structure shows many characteristics required to make it a candidate for the next-generation multijunction solar cells, which means this design can be used as the third junction of future-generation ultrahigh-efficiency three- and four-junction devices.
Japan Society of Applied Physicsの論文
2006-07-25