Directional emission in strain-balanced quantum well solar cells

• Published in: 2009 34th IEEE Photovoltaic Specialists Conference (PVSC) pp. 000071 - 000075
• Main Authors: Adams, J.G.J., Roberts, J.S., Hill, G., Ekins-Daukes, N.J., Barnham, K.W.J.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-06-2009
• Subjects: Absorption; Distributed Bragg reflectors; Gallium arsenide; Optical losses; Photovoltaic cells; Radiative recombination; Reflectivity; Substrates; Tensile strain; Voltage
• ISBN: 1424429498; 9781424429493
• ISSN: 0160-8371
• DOI: 10.1109/PVSC.2009.5411734

The major loss mechanism in the strain-balanced quantum well solar cell is through radiative recombination in the quantum wells. This loss can be reduced through optical manipulation, as fundamentally the radiative emission need only occur in the direction of absorption. In strained quantum well systems, the valence band splits into heavy hole and light hole bands leading to the restriction of emission in the plane of the quantum wells. This suppression of the radiative recombination leads to a higher power conversion efficiency limit.