Direct Semiconductor Bonded 5J Cell for Space and Terrestrial Applications

Chiu, Philip; Law, D. C.; Woo, Robyn L.; Singer, S.; Bhusari, D. M.; Hong, Wonbin; Zakaria, A.; Boisvert, Joseph; Mesropian, S.; King, Richard R.; Karam, N.H.

doi:10.1109/jphotov.2013.2279336

Cited by 111 publications

(64 citation statements)

References 7 publications

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“…Wafer-bonding techniques have also been applied for fabricating the multi-junction solar cells. [15][16][17][18] However, conventional wafer-bonding techniques, such as plasmaactivated bonding and fused bonding, have a disadvantage in that they generally require high-temperature annealing, which could result in wafer bending and void formation at a bonding interface owing to the difference in thermal expansion coefficients. Even in the case of wafer-bonding between lattice-matched wafers, cracks and defects could be generated.…”

Section: Introductionmentioning

confidence: 99%

III–V compound semiconductor multi-junction solar cells fabricated by room-temperature wafer-bonding technique

Arimochi

Watanabe

Yoshida

et al. 2015

Jpn. J. Appl. Phys.

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We have developed III-V compound semiconductor multi-junction solar cells by a room-temperature wafer-bonding technique to avoid the formation of dislocations and voids due to lattice mismatch and thermal damage during a conventional high-temperature wafer-bonding process. First, we separately grew an (Al)GaAs top cell on a GaAs substrate and an InGaAs bottom cell on an InP substrate by metal solid source molecular beam epitaxy. Thereafter, we successfully bonded these sub-cells by the room-temperature wafer-bonding technique and fabricated (Al)GaAs k InGaAs wafer-bonded solar cells. To the best of our knowledge, the obtained GaAs k InGaAs and AlGaAs k InGaAs wafer-bonded solar cells exhibited the lowest electrical and optical losses ever reported. The AlGaAs k InGaAs solar cells reached the maximum efficiency of 27.7% at 120 suns. These results suggest that the room-temperature wafer-bonding technique has high potential for achieving higher conversion efficiencies.

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Section: Introductionmentioning

confidence: 99%

III–V compound semiconductor multi-junction solar cells fabricated by room-temperature wafer-bonding technique

Arimochi

Watanabe

Yoshida

et al. 2015

Jpn. J. Appl. Phys.

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“…If the upper tandem is improperly biased at V oc as shown by the green-dashed curve, the lower tandem J sc increases by ~0.6 mA/cm 2 due to the artificially enhanced luminescent coupling. Under the proper conditions, the cumulative efficiency of the tandem is 30.21% + 8.54% = 38.8 ± 1 %, which is equal to the best reported efficiencies for twoterminal cells at 1 sun [12]. The uncertainty reflects an estimated 3% relative uncertainty in the individual measurements.…”

Section: Resultsmentioning

confidence: 62%

“…The upper tandem was grown inverted and the substrate was removed as part of the processing [19]. The lower tandem was grown upright on n-type InP and the substrate remained part of the final structure; this tandem is a version of the one included in the 5J wafer-bonded cell described in [12]. The process can be adapted to include an inverted bottom tandem.…”

Section: Solar Cell Fabricationmentioning

confidence: 99%

Optically Enhanced Photon Recycling in Mechanically Stacked Multijunction Solar Cells

Steiner

Geisz

Ward

et al. 2016

IEEE J. Photovoltaics

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Abstract-Multij unction solar cells can be fabricated by mechanically bonding together component cells that are grown separately. Here, we present four-junction four-terminal mechanical stacks composed of GalnP/GaAs tandems grown on GaAs substrates and GalnAsP/GalnAs tandems grown on InP substrates. The component cells were bonded together with a low-index transparent epoxy that acts as an angularly selective reflector to the GaAs bandedge luminescence, while simultaneously transmitting nearly all of the subbandgap light. As determined by electroluminescence measurements and optical modeling, the GaAs subceU demonstrates a higher internal radiative limit and, thus, higher subceU voltage, compared with GaAs subceUs without the epoxy reflector. The best cells demonstrate 38.8 ± 1.0% efficiency under the global spectrum at 1000 W/m 2 and ~ 42% under the direct spectrum at ~100 suns. Eliminating the series resistance is the key challenge for further improving the concentrator cells.

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“…For example, a 5 junction GaAs/InP cell with an efficiency of 38.8% is demonstrated. [35] To pump the thermal energy from the dark world 31 Figure 4 a) The energy converting efficiency and yield of current PV devices (yellow) and the proposed infrared devices (red). b) The efficiency and energy gap of materials currently used in PV devices (yellow region) and that may be applied in the proposed infrared PV devices (red region).…”

Section: Feasibility For Pumping Thermal Energy From the Environmentmentioning

confidence: 99%

To pump the thermal energy from the dark world

Xu¹,

Su²

2014

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With a global average temperature around 300 K, the surface of the Earth emits a huge thermal energy in the form of long wave radiation, making it a warm thermal source in the cold universe. While living on the surface of the Earth, theoretically we are merged in the ocean of thermal radiation at the nominal rate of 100-300 Wm -2 at different seasons and in different regions. Here we present a proposal for pumping and utilizing this kind of thermal energy, even from the dark world at night or under the ground.Keywords: Thermal radiation; blackbody radiation; infrared electromagnetic wave; photovoltaic device. I. Endless solar energy sourceThe development of human civilization faces a tough problem that the most easily available "fossil energy", in the forms of petroleum oil, natural gas and coal, is going to exhaust in a one or a few hundred years. People in rich areas have been consuming more energy and natural resources than they should. For example, with its 4.5% of the world population (7.0 billion in 2014), the United States consumes around 20% of the total yearly energy cost by human being. China, with a 20% of the world population, is now taking more than 20% of the yearly energy the world consumed. These is no sign that people are going to change their 26 Shengyong Xu and Xiaohui Suways of living on the earth in the near future, in terms of enjoying the benefits of electricity and zillions of industry products, such as semiconductor devices, car, airplane, as well as city life. Clearly this mode is not sustainable in the time scale of one thousand year.The best and probably final solution for the energy crisis is to develop fusion technology that uses the almost infinite hydrogen element in seas and oceans.[1] The International Thermonuclear Experimental Reactor (IETR) project [2] in Europe has been going on for 7 years. It indeed aims at making a manmade sun on the surface of the earth, which faces incredible technical challenges and may cost a century or longer.Fortunately, the solar energy we received on the earth is also "endless". It is known that the surface temperature of the sun is around 6,000 K. By a rough estimation, considering the sun as a blackbody, its radiation spectrum follows the Plank formula. In Figure 1a, curve "A" plots this spectrum of the sunshine flux at the surface of outer atmosphere, and curve "B" is the sunlight flux measured at the surface of earth. The missing part is reflected, or scattered, or adsorbed on its way penetrating the atmosphere. The Solar Constant, 1.3 kW/m 2 , is the energy flux received at the surface of the earth atmosphere. As a result, 0.9 hour of this radiation energy at the earth surface is currently equal to the total energy consumed by human per year, i.e., 5.24 × 10 20 J. However, to date the solar energy only contributes around 2% in the total world energy recipe.[3] If in the next half a century, if this portion is increased to 50%, we may earn more time for the development of fusion technology. Figure 1Energy intensity spectra of electroma...

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Direct Semiconductor Bonded 5J Cell for Space and Terrestrial Applications

Cited by 111 publications

References 7 publications

III–V compound semiconductor multi-junction solar cells fabricated by room-temperature wafer-bonding technique

III–V compound semiconductor multi-junction solar cells fabricated by room-temperature wafer-bonding technique

Optically Enhanced Photon Recycling in Mechanically Stacked Multijunction Solar Cells

To pump the thermal energy from the dark world

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