GaAs and GaSb based solar cells for concentrator and thermophotovoltaic applications

Abstract

The paper presents the results of the development of AIGaAs/GaAs and GaSb cells, manufactured for tandem solar cells and designed for point and line-focus concentrator modules. The maximum efficiency of 23-23.6% (25'C, AMO) under 20-70 suns was achieved in the AIGaAs/GaAs infrared transparent cells with prismatic cover. The efficiency of 27.5% under AM1.5, 140 suns has been achieved.. The cells based on GaSb homo-junctions, Zn-diffused structures have been developed for tandems and thermophotovoltaic (TPV) applications. AM 1.5 efficiencies as high as 6.7% behind the GaAs filter for concentration ratio of 240 suns were achieved.Lattice matched p-n InGaSbAs-nGaSb heterostructures have been fabricated by LPE and Zn-diffusion method. The longwavelength edge of photosensitivity of these cells is 2.15-2.2 pm. IhlTRODUCTlONThe tandem solar cells have been realized recently in both mechanically stacked [l] and monolithic [2,3] constructions. The maximum efficiencies of about 30% (AMO) and 35% (AM 1.5) were achieved in a mechanically stacked concentrator tandem solar cells on the basis of AlGaAs/GaAs top cells and GaSb bottom cells [l]. MOCVD has become the main method for preparation of high efficiency AIGaAs/GaAs cell heterostructures. The nontoxic, inexpensive low-temperature LPE-method was used in our work for reproducible growth of the AIGaAs/GaAs structures [4, 51. The work on development of the GaSb and InGaSbAsjGaSb structures for tandems and thermophotovoltaics is in progress. INFRARED TRANSPARENT AIGaAs/GaAs SOLAR CELLSAIGaAs/GaAs heterostructures were fabricated by low temperature (600-400°C) liquid phase epitaxy [4,5]. The structures with p+GaAs top contact layer, 0.05-0.07 pm wide-gap AI , , , Ga, , , As window layer, 0.4-0.6pm p-GaAs photoactive layer, 3 lum n-GaAs layer and back surface field AI, ,Ga,,As layer have been manufactured (see 143 0-7803-3166-4/96/$5.(30 0 1996 IEEE

Formation of A3B5 ternary solid solutions on GaSb plates by solid- state substitution reactions

“…WOW is transparent for underlying layer radiation and at the same time is a barrier which prevents currier migration on the surface where probability of their nonradiative recombination is great [2].…”

“…In this case, the presence of wide-bandgap optical window (WOW) on surface of each of PC element plays essential role [2]. WOW is the ultra-thin layer of solid solution isomorphous with the device structure and having wider bandgap comparing to the underlying layers.…”

Technology update on patent and development trend of power over fiber: a critical review and future prospects

“…InGaAs and GaSb have the same energy gap and the output voltage level of 0.7 eV and 0.5 V, respectively 7 . The efficiency of these materials for PoF mechanism in different experiments were reported; Si has a maximum efficiency of 42.9% at 980 nm, 54 whereas InGaAs and GaSb have 45% and 49% peak efficiency at 1550 nm 30 and 1680 nm 55 respectively. GaAs is a good material for PV since it has a direct and large bandgap material and has high tolerance over a wide range of temperatures.…”

Modelado y fabricación de células fotovoltaicas de GaSb : Aplicación a sistemas termofotovoltaicos

“…De la misma manera, en el Ioffe Institute de San Petersburgo se inició la investigación en células de GaSb también a primeros de los 90 [Andreev94] [Khvostikov95] [Sulima95] [Andreev96]. La configuración típica de dispositivo fabricado se basó también en dos difusiones de Zn en GaSb, con un objetivo similar al perseguido por los investigadores de la Boeing: formar un emisor muy superficial en el área iluminada y más profundo en la región de los contactos metálicos delanteros, para minimizar las fugas de corriente por cortocircuitos de la unión en el paso de aleado del contacto delantero.…”

“…de dispositivos termofotovoltaicos p/n está basado en AuGe. A veces se utiliza únicamente dicha aleación[Andreev98] [Sulima03a], otras se incorpora posteriormente una capa de Au (AuGe/Au)[Andreev96] [Bett97b], y en algunas se incluye en la metalización una capa de Ni, favoreciendo los procesos de recristalización en fase sólida (AuGe/Ni/Au)[Andreev01]. Las temperaturas de aleado suelen rondar los 300ºC[Andreev98].…”