Imperial College London
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DrDiegoAlonso Alvarez

Central Faculty, Information & Communication Technologies

Head of Research Software Engineering
 
 
 
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Contact

 

+44 (0)20 7594 9491d.alonso-alvarez Website

 
 
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Location

 

Sherfield BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Alonso-Alvarez:2014:10.1063/1.4894424,
author = {Alonso-Alvarez, D and Thomas, T and Fuehrer, M and Hylton, NP and Ekins-Daukes, NJ and Lackner, D and Philipps, SP and Bett, AW and Sodabanlu, H and Fujii, H and Watanabe, K and Sugiyama, M and Nasi, L and Campanini, M},
doi = {10.1063/1.4894424},
journal = {Applied Physics Letters},
title = {InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells},
url = {http://dx.doi.org/10.1063/1.4894424},
volume = {105},
year = {2014}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - 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 wires instead of wells could have several unexpected consequences for the performance of the MQW solar cells, both positive and negative, that need to be assessed to achieve high conversion efficiencies. In this letter, we study QWR properties from the point of view of their performance as solar cells by means of transmission electron microscopy, time resolved photoluminescence and external quantum efficiency (EQE) using polarised light. We find that these QWRs have longer lifetimes than nominally identical QWs grown on exact [100] GaAs substrates, of up to 1 μs, at any level of illumination. We attribute this effect to an asymmetric carrier escape from the nanostructures leading to a strong 1D-photo-charging, keeping electrons confined along the wire and holes in the barriers. In principle, these extended lifetimes could be exploited to enhance carrier collection and reduce dark current losses. Light absorption by these QWRs is 1.6 times weaker than QWs, as revealed by EQE measurements, which emphasises the need for more layers of nanostructures or the use light trapping techniques. Contrary to what we expected, QWR show very low absorption anisotropy, only 3.5%, which was the main drawback a priori of this nanostructure. We attribute this to a reduced lateral confinement inside the wires. These results encourage further study and optimization of QWRs for high efficiency solar cells.
AU  - Alonso-Alvarez,D
AU  - Thomas,T
AU  - Fuehrer,M
AU  - Hylton,NP
AU  - Ekins-Daukes,NJ
AU  - Lackner,D
AU  - Philipps,SP
AU  - Bett,AW
AU  - Sodabanlu,H
AU  - Fujii,H
AU  - Watanabe,K
AU  - Sugiyama,M
AU  - Nasi,L
AU  - Campanini,M
DO  - 10.1063/1.4894424
PY  - 2014///
SN  - 1077-3118
TI  - InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells
T2  - Applied Physics Letters
UR  - http://dx.doi.org/10.1063/1.4894424
UR  - http://hdl.handle.net/10044/1/41074
VL  - 105
ER  -
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