InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

• DOI: 10.1063/1.4894424
• Publication Date: 2014-09-02T14:27:35Z
• Authors: D. Alonso-Álvarez; T. Thomas; M. Führer; N. P. Hylton; N. J. Ekins-Daukes; D. Lackner; S. P. Philipps; A. W. Bett; H. Sodabanlu; H. Fujii; K. Watanabe; M. Sugiyama; L. Nasi; M. Campanini
• Keywords: Quantum Efficiency; Quantum wire; Indium gallium arsenide

Quantum wires (QWRs) form naturally when growing strain balanced InGaAs/GaAsP multi-quantum wells (MQW) on GaAs [100] 6° misoriented substrates under the usual growth conditions. The presence of instead could have several unexpected consequences for performance MQW solar cells, both positive and negative, that need to be assessed achieve high conversion efficiencies. In this letter, we study QWR properties from point view their as cells by means transmission electron microscopy, time resolved photoluminescence external quantum efficiency (EQE) using polarised light. We find these QWRs longer lifetimes than nominally identical QWs grown exact substrates, up 1 μs, at any level illumination. attribute effect an asymmetric carrier escape nanostructures leading a strong 1D-photo-charging, keeping electrons confined along wire holes in barriers. principle, extended exploited enhance collection reduce dark current losses. Light absorption is 1.6 times weaker QWs, revealed EQE measurements, which emphasises more layers or use light trapping techniques. Contrary what expected, show very low anisotropy, only 3.5%, was main drawback priori nanostructure. reduced lateral confinement inside wires. These results encourage further optimization cells.