Trustworthy Systems

Limits to the efficiency of silicon multilayer thin film solar cells


Stuart R. Wenham, Martin A. Green, Sean Edmiston, Patrick Campbell, Linda Koschier, Christiana B. Honsberg, Alistair B. Sproul, David Thorpe, Zhengrong Shi and Gernot Heiser

    School of Computer Science and Engineering
    Sydney 2052, Australia


Thin film crystalline silicon solar cells can only achieve high efficiencies if light trapping can be used to give a long optical path length, while simultaneously achieving near unity collection probabilities for all generated carriers. This necessitates a supporting substrate of a foreign material, with refractive index compatible with light trapping schemes for the silicon. The resulting inability to nucleate growth of crystalline silicon films of good crystallographic quality on such foreign substrates, at present, prevents the achievement of high efficiency devices using conventional single junction solar cell structures. The parallel multijunction solar cell provides a new approach for achieving high efficiencies from very poor quality material, with near unity collection probabilities for all generated carriers achieved through appropriate junction spacing. Heavy doping is used to minimise the dark saturation current contribution from the layers, therefore allowing respectable voltages. The design strategy, corresponding advantages, theoretical predictions and experimental results are presented.

BibTeX Entry

    address          = {Waikoloa, HI, USA},
    author           = {Stuart R. Wenham and Martin A. Green and Sean Edmiston and Patrick Campbell and Linda Koschier and
                        Christiana B. Honsberg and Alistair B. Sproul and David Thorpe and Zhengrong Shi and Gernot Heiser},
    booktitle        = {1st World Conference on Photovoltaic Energy Conversion},
    month            = dec,
    organization     = {IEEE},
    pages            = {1234--1241},
    title            = {Limits to the Efficiency of Silicon Multilayer Thin Film Solar Cells},
    year             = {1994}