Photocurrent Generation by Two-Step Photon Absorption With Quantum-Well Superlattice Cell

Author

Sugiyama, Masakazu ; Wang, Yannan ; Watanabe, K. ; Morioka, T. ; Okada, Yoshitaka ; Nakano, Yoshiaki

Author_Institution

Institute of Engineering Innovation and the Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Japan

Volume

2

Issue

3

fYear

2012

fDate

7/1/2012 12:00:00 AM

Firstpage

298

Lastpage

302

Abstract

We have observed photocurrent due to two-step photon absorption using an InGaAs/GaAsP strain-balanced quantum-well (QW) superlattice cell, with barrier thickness of 3 nm. Upon infrared irradiation with a filtered air mass 1.5 light source (λ > 1.4 μm), quantum efficiency was increased by 0.8% at the wavelength range corresponding to the absorption of the quantum wells. No efficiency enhancement was observed either for a conventional QW solar cell with thick (11 nm) barriers or for a GaAs pin cell, suggesting that efficient separation of photogenerated electrons and holes in the superlattice is essential for this achievement of two-step photon absorption. The quantum efficiency of such two-step photocurrent generation can be enhanced by specific tailoring of a superlattice layer structure, by which the QW superlattice will be a possible active region for an intermediate-band solar cell.

Keywords

Absorption; Gallium arsenide; Photoconductivity; Photonics; Photovoltaic cells; Quantum wells; Superlattices; Intermediate-band solar cell; quantum-well (QW) superlattice; two-step photon absorption;

fLanguage

English

Journal_Title

Photovoltaics, IEEE Journal of

Publisher

ieee

ISSN

2156-3381

Type

jour

DOI

10.1109/JPHOTOV.2012.2196258

Filename

6212296