High-efficiency AlGaAs-GaAs solar cells with internal Bragg reflector

Conference · Sat Dec 31 00:00:00 EST 1994

OSTI ID:191149

Andreev, V M; Komin, V V; Kochnev, I V; Lantratov, V M; Shvarts, M Z ^[1]

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1. Russian Academy of Sciences, St. Petersburg (Russian Federation). A.F. Ioffe Physico-Technical Inst.

The work presents an investigation of solar cells (SCs) based on AlGaAs/GaAs heterostructures with internal Bragg reflectors grown by low-pressure MOCVD on n-GaAs substrates in a horizontal resistively heated reactor. The typical structure consists of: Bragg reflector (BR) having 12 periods, n-GaAs base layer with the thickness of 1,500--2,000 nm, 400--500 nm thick p-GaAs emitter, 70 nm thick p-AlGaAs passivating window and top p-GaAs contact layers. The BR with the reflectance maximum centered at the wavelength of 860 nm consists of twelve pairs of AlAs/GaAs layers. The resulting BR thicknesses is 71.6 nm for A.As and 59 nm for GaAs. In this case the peak of reflectance spectrum is in the area of 830--900 nm where the reflectance is close to unit. This multi-layer quasi-dielectric stack selectively reflect weakly absorbed photons with energies near the GaAs band gap for a second pass through the photoactive region increasing the photocurrent. The employment of the BR allows to increase the external quantum efficiency in the long wavelength range of the spectrum and to fabricate simultaneously a thinner n-GaAs base layer. The use of the internal BR, Ta{sub 2}O{sub 5} for antireflecting coating and prismatic cover allowed them to obtain efficiency of 23.4% (17.7 suns, AM0, 25 C) and 27.2% (23.4 suns, Am 1.5).

• OSTI ID: 191149
• Report Number(s): CONF-941203-; ISBN 0-7803-1459-X; TRN: IM9610%%150
• Resource Relation: Conference: 1. world conference on photovoltaic energy conversion, Waikoloa, HI (United States), 5-9 Dec 1994; Other Information: PBD: 1994; Related Information: Is Part Of 1994 IEEE first world conference on photovoltaic energy conversion: Conference record of the twenty-fourth IEEE photovoltaic specialists conference -- 1994. Volume 2; PB: 1268 p.
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
ALUMINIUM ARSENIDE SOLAR CELLS
PERFORMANCE
GALLIUM ARSENIDE SOLAR CELLS
ALUMINIUM ARSENIDES
CHEMICAL VAPOR DEPOSITION
BRAGG REFLECTION
GALLIUM ARSENIDES
ORGANOMETALLIC COMPOUNDS
DOPED MATERIALS
SILANES
MAGNESIUM
ANTIREFLECTION COATINGS
TANTALUM OXIDES
ELECTRIC CONTACTS
SCANNING ELECTRON MICROSCOPY
QUANTUM EFFICIENCY
CURRENT DENSITY
ELECTRIC POTENTIAL
FILL FACTORS