Progress in narrow gap InGaAs/InP element for tandem solar cells

Author

Karlina, L.B. ; Kazantsev, A.B. ; Shvarts, M.Z.

Author_Institution

A.F. Ioffe Physicotech. Inst., Acad. of Sci., St. Petersburg, Russia

Volume

2

fYear

1994

fDate

5-9 Dec 1994

Firstpage

1918

Abstract

Narrow gap In_0.53Ga_0.47As/InP solar cells illuminated through a transparent InP substrate are the best candidates for fabrication on their base bottom cells combined with GaAs or InP top cells in mechanically stacked tandem concentrator solar cells. The In _0.53Ga_0.47As/InP (hereafter InGaAs) heterostructures were grown by liquid phase epitaxy. They consist of four epitaxial layers: n-InP (buffer); n-InGaAs and p-InGaAs (photoactive); p⁺-InGaAs (barrier+contact). This work describes the influence of an InP/InGaAs window/emitter interface region, emitter and base thickness on the collection efficiency of solar cells and the short-circuit current. The thick (1.7-2.0 μm) and slightly doped emitter maximizes the photocarrier generation in the emitter and space charge depletion region. Our study shows that collection efficiency values as high as 90% were measured in the spectral range of 1000-1600 nm for developed cells. It allowed us to obtain a photocurrent of 30.6 mA/cm² (AM0, 1 Sun). This result was confirmed in the NASA LeRC

Keywords

III-V semiconductors; energy gap; gallium arsenide; indium compounds; liquid phase epitaxial growth; p-n heterojunctions; photoconductivity; semiconductor epitaxial layers; semiconductor growth; solar cells; solar energy concentrators; space charge; substrates; 1.7 to 2 mum; 1000 to 1600 nm; 90 percent; AM0; In_0.53Ga_0.47As-InP; InP/InGaAs window/emitter interface; barrier; base thickness; bottom cells; buffer; collection efficiency; contact; emitter thickness; heterostructures; liquid phase epitaxy; mechanically stacked; n-InGaAs; n-InP; narrow gap In_0.53Ga_0.47As/InP solar cells; p-InGaAs; p⁺-InGaAs; photoactive layer; photocarrier generation; short-circuit current; slightly doped emitter; space charge depletion region; transparent InP substrate; Epitaxial growth; Epitaxial layers; Fabrication; Gallium arsenide; Indium gallium arsenide; Indium phosphide; Photovoltaic cells; Solar power generation; Space charge; Substrates;

fLanguage

English

Publisher

ieee

Conference_Titel

Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on

Conference_Location

Waikoloa, HI

Print_ISBN

0-7803-1460-3

Type

conf

DOI

10.1109/WCPEC.1994.520743

Filename

520743