Design of a three-layer antireflection coating for high efficiency indium phosphide solar cells using a chemical oxide as first layer

Conference · Sun Oct 01 04:00:00 EDT 1995

OSTI ID:177660

Moulot, J; Faur, M; Faur, M; Goradia, C; Goradia, M; Bailey, S ^[1]

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1. Cleveland State Univ., OH (United States)

It is well known that the behavior of III-V compound based solar cells is largely controlled by their surface, since the majority of light generated carriers (63% for GaAs and 79% for InP) are created within 0.2 mu m of the surface of the illuminated cell. Consequently, the always observed high surface recombination velocity (SRV) on these cells is a serious limiting factor for their high efficiency performance, especially for those with p-n junction made by either thermal diffusion or ion implantation. A good surface passivation layer, ideally a grown oxide as opposed to a deposited one, will cause a significant reduction in the SRV without adding interface problems, thus improving the performance of III-V compound based solar cells. Another significant benefit to the overall performance of the solar cells can be achieved by a substantial reduction of their large surface optical reflection by the use of a well designed antireflection (AR) coating. In this paper, the authors demonstrate the effectiveness of using a chemically grown thermally and chemically stable oxide, not only for surface passivation but also as an integral part of a 3-layer AR coating for thermally diffused p+n InP solar cells. A phosphorus-rich interfacial oxide, In(PO3)3, is grown at the surface of the p+ emitter using an etchant based on HNO3, o-H3PO4 and H2O2. This oxide has the unique properties of passivating the surface as well as serving as an efficient antireflective layer yielding a measured record high AMO open-circuit voltage of 890.3 mV on a thermally diffused InP(Cd,S) solar cell. Unlike conventional single layer AR coatings such as ZnS, Sb2O3, SiO or double layer AR coatings such as ZnS/MgF2 deposited by e-beam or resistive evaporation, this oxide preserves the stoichiometry of the InP surface.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
• OSTI ID: 177660
• Report Number(s): N--96-15042; NASA-CP--10180; NAS--1.55:10180; E--9943; NIPS--95-05337; CONF-9510288--
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
ANTIREFLECTION COATINGS
INDIUM PHOSPHATES
INDIUM PHOSPHIDE SOLAR CELLS
P-N JUNCTIONS
PASSIVATION
SURFACE TREATMENTS