ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
A series of systematic studies have been made on both optimum design and preparation technology of high efficiency a-Si/a-Si/a-SiGe triple-junction solar cells. It has been found that current matching is one of the key factors affecting the fill factor of two-terminal tandem solar cells, and excess carrier recombination at the p-n interface acting as an internal electrode is dominated by the density of the minority carriers, interfacial states, and geometrical factor match of the materials at the p-n interface. In this work, μc-Si:H with wide band gap and high conductivity, which was prepared at low substrate temperature, was used as an n layer of a-Si:H solar cells. In order to improve the n-i interface property, a novel approach involving the insertion of an n−a-Si:H buffer layer at the n-i interface was developed. The experimental results show that the buffer layer of appropriate thickness could enhance the fill factor and open circuit voltage of a-Si:H based solar cells. In addition, highly photosensitive a-SiGe:H(F) films used for a bottom cell in a-Si/a-Si/a-SiGe triple junction solar cells have been obtained by glow discharge of a gas mixture (SiH4—GeF4—H2) under conditions of high hydrogen dilution ratio and low deposition pressure. At present, the conversion efficiency of the a-Si/a-Si/a-SiGe triple-junction solar cell of 11.5% with Voc=2.48 V, Jsc=6.58 mA/cm2, and FF=70.4% has been obtained under AM1(100 mW/cm2) illumination by optimization of the solar cell structure and preparation technology.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.357011
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