A 532 nm laser was used to homogeneously illuminate the entire field of view under a microscope objective, allowing the pl signal coming from a million points to. Highefficiency gaas thinfilm solar cell reliability nrel pv module reliability workshop, feb. A short base with a highly reflective back contact enables a longwavelength photon to be absorbed near the pn junction by. The heterostructure of the gaas solar cell shown in fig. Later, dual and triplejunction solar cells based on gaas with germanium and indium gallium phosphide layers were developed as the basis of a triplejunction solar cell. Solar cell structure gainp 2 gaas ge method metal organic vapor phase epitaxy device design monolithic, two terminal triple junction. Gallium arsenidebased multijunction solar cells are the most efficient solar cells to date, reaching the record efficiency of 42. In 1961, shockley and queisser showed that the maximum theoretical ef. The solar panels of a typical satellite in low earth orbit lose 15% of its power generating potential in 5 years. Em microelectronic embc01 beacon 11 solar beacon in a tiny package operates forever as long as there is a few hours of daily light. This type of cell has the advantage of all metallization residing on the back of the cell, giving the opportunity to independently optimize the front and back of the cell for optical and electrical performance, respectively 3. The fabrication procedure and the results of characterization tests are discussed below. Study of the electrical parameters degradation of gaas sub. Solar water splitting by photovoltaicelectrolysis with a.
However, high fabrication costs have made gaas based solar cells prohibitively expensive for mass. Introduction the power output of solar cells is severely reduced by damages caused by radiation. Solar cell is an optoelectronic device that can directly convert solar energy into electrical energy 1. Ultralight flexible ingapin gaas tandem solar cells with conversion efficiency of 28. Backcontacted and small form factor gaas solar cell. Pdf ingapgaasbased multijunction solar cells mitsuru. It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, or resistance, vary when exposed. Oct 31, 2016 the solar cell was kept at 25 c on a water cooler stage and positioned under the multisun solar simulator.
Gallium arsenide high power thin films nanoflex power. Single junction solar cells photovoltaics lab ioffe. Figure 1c shows optical micrographs of a gaas solar cell printed on a plain and nanostructured silver substrate, respectively. Abstract the electrical performance of gaas solar cells was characterized as a function of irradiation with protons and electrons with the underlying goal of producing solar cells suitable for use in space.
The allbackcontact solar cell can reduce the shadow loss. Though gallium arsenide gaas solar cells are proven to be relatively stable in space working conditions, they are prone to the effects of aging, which deteriorate their characteristics. A silicon solar cell with silicongermanium filter using a step cell design large and a gallium arsenide phosphide layer on silicon step cell proofofconcept solar cell small. Gainp top cell and the gaas middle cell, in order to increase photogeneration in the middle cell 1,2. Germaniumonnothing for epitaxial liftoff of gaas solar. The design and optimization of gaas single solar cells using. Highefficiency gaas thinfilm solar cell reliability author. Microsystemsenabled photovoltaics is an emerging area.
Therefore, we try optimize the design of allbackcontact gaas solar cells in this paper. All solar cells include the latest triple and quadruple junction technology, where gainp gaas ge layers are grown on a germanium substrate and the whole product range benefits from many years experience on the space. The distance between the cell and the solar simulator was adjusted so that. Gallium arsenide is suited to use in solar cells due to its 1. A prototypical wafer bonded fourjunction would consist of gainp gaas ingaasp ingaas 1. Pdf numerical simulation of gaas solar cell aging under.
Multijunction solar cell an overview sciencedirect topics. Center for semiconductor research research triangle. Confidential and proprietary information of alta devices, inc. Article germaniumonnothing for epitaxial liftoff of gaas solar cells sanghyun park,1 john simon, 2kevin l. We introduce a novel germaniumonnothing gon technology to fabricate ultrathin ge films for lightweight and thin gaas solar cells. For both gaas and ingap, high speed growth results in decreasing of cell efficiency, which defects and dislocations are responsible. Performing organization name and address jet propulsion laboratory california institute of technology 4800 oak grove drive pasadena, california 91109 12. Radiation analysis of ingapgaasge and gaasge solar cell. Germaniumonnothing for epitaxial liftoff of gaas solar cells. The efficiency of the cells is 29% under am0 illumination. Investigation of low cost substrate approaches for iiiv solar cells marlene lydia lichty old dominion university follow this and additional works at.
Thin film gaas solar cells on glass substrates by epitaxial. New solar cell is more efficient, costs less than its. Result is the solar energy needed in one day in whrs. Compound semiconductors from iiiv materials such as gallium arsenide gaas, indium phosphide inp and gallium indium phosphide gainp are used. A solar cell is a pn junction with a narrow and more heavily doped nregion. Multijunction photovoltaic technologies for high performance. Crystalline silicon requires a layer 100 microns or more. Increasing the number of junctions generally offers the potential to reach even higher efficiencies, but material quality and the choice of bandgap energies turn out to be even more importance than the.
This process requires firstly, a material in which the absorption of light raises an electron to a higher energy state. Since gaas has excellent material properties, the optimization of structure design becomes more critical to boost the performance. There are two common structures for the gaas solar cell. Solar cells made from iiiv semiconductors like gaas have the highest energycon version ef. A wide variety of gaas solar cell options are available to you, there are 435 suppliers who sells gaas solar cell on, mainly located in asia. A lattice mismatch of about 4% exists between the materials used, but this lattice mismatch does not. Proton and electron radiation analysis of gainpzgaas solar cells. Figure 1 represents the normal ized curves of power versus radiation dose used in the study.
They were originally developed for special applications such as satellites and space investigation. The highest efficiency cell had a lateral size of 500 m and a. Image of a printed gaas solar cell with a size 10 x 10 mm2 on a glass substrate, with simple, metal grid contacts. Mars rover powered by multijunction cells this very successful space cell is. Fourterminal mechanically stacked gaassi tandem solar cells. Plasmonically enhanced spectral upconversion for improved. The cells have an alingap gaas ingaas structure and are grown using metalorganic chemical vapor deposition mocvd on a gaas substrate. The lifetime of solar cells is restricted by the degree of. Using microsystem tools, we created sturdy 3 m thick devices with lateral dimensions of 250 m, 500 m, 1 mm, and 2 mm. In the 1990s, gaas solar cells took over from silicon as the cell type most commonly used for photovoltaic arrays for satellite applications. E g, v oc, j sc, ff and z of single junction solar cells ignoring the series and shunt resistances. Pdf iiiv material solar cells for space application.
The solar cell was illuminated by a spectral illumination source of am1. Excellent stability of the flexible solar cell characteristics under different bending conditions in conjunction with its remarkably high specific power of 1995 wkg. Triplejunction ingapgaasge solar cells integrated with. Algainp gaas tandem solar cells for power conversion at elevated temperature and high concentration emmett e. Young, and jihun oh1,4 5 summary solar cells from iiiv materials offer outstanding light conversion ef. New process could make gallium arsenide cheaper for. It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, or resistance, vary when exposed to light individual solar cell devices can be. Solar cell degradation gallium arsenide solar cells have a recognized advantege over silicon solar cells in tenus of radi ation tolerance.
High speed movpe for ingapgaas multijunction solar cells. Jul 20, 2016 the gaas thinfilm solar cell is a top contender in the thinfilm solar cell market in that it has a high power conversion efficiency pce compared to that of other thinfilm solar cells. Friedman 1, nikhil jain 1, paul sharps 2, claiborne mcpheeters 2, yukun sun 3, minjoo l. This solar cell has been under development at varian for the 1 ast several years. The highest solar cell conversion efficiencies are achieved with fourjunction devices under concentrated sunlight illumination. Gaas substrate gaas substrate temporary carrier temporary carrier 1. Keywords gaas solar cells, ingap gaas ge solar cells, protons, electrons, irradiation, fluence, energy. Response of single junction gaasgaas and gaasge solar. Solar cell is a device to convert the sunlight energy to a electric current. Their high efficiency comes from the possibility to grow three or more junctions for the same cell. Highly efficient singlejunction gaas thinfilm solar cell on. Drawbacks, opprtunities, highefficiency concepts and concentrators and multijunction technology are covered. Characterization of production gaas solar cells for space. Compared with previous porous ge studies, we significantly improve the surface quality of reformed ge by engineering.
The electrical performance of gaas solar cells was characterized as a function of irradiation with protons and electrons with the underlying goal of producing solar cells suitable for use in space. Gaas has an absorptivity so high it requires a cell only a few microns thick to absorb sunlight. Light shining on the solar cell produces both a current and a voltage to generate electric power. A conventional ingapingaasge solar cell structure was epitaxially grown on 180lm thick 400 diameter ptype 100 ge substrates at 640 c using veecos k475 commercial mocvd reactor. Accordingly, the tio 2 al 2 o 3 bilayer arc on the solar cell transforms the refractive index of the pmma into that of a gaas based solar cell heterostructure. Different cell architectures are under development, all targeting an ideal bandgap combination close to 1. Pvconversion efficiencies greater than 25% have been achieved on singlejunction solar cells fabricated in epitaxially grown gaas on a singlecrystal substrate. The study described here reports orr a series of investigations to correlate solar cell yield with substrate quality, growth techniques, layer composition, and metallization processes.
Steiner 1 1national renewable energy laboratory, golden, colorado, united states 2solaero technologies corp. This configuration allows illumination through the noncontact side of the cell, which increases its collection area and shortcircuit current. Investigation of low cost substrate approaches for iiiv. Gon membranes formed by reorganization of cylindrical pores during annealing enable the growth and transfer of gaas cells and substrate reuse. This thesis presents new results on wafer bonding and layer transfer for integration of materials with large lattice mismatch, as well as modeling work to better understand the key material parameters in the design of new multijunction solar cells.
Gaas is especially suitable for use in multijunction and highefficiency solar cells for several reasons. Doubling the power output of bifacial thinfilm gaas solar. The density of the shortcircuit photocurrent increases from 25 ma. Quantum engineering of inas gaas quantum dot based intermediate band solar cells neil s.
Wafer bonding is used in this work to combine materials with a significant lattice mismatch. Highefficiency gaas thinfilm solar cell reliability. The photovoltaic parameters such as open circuit voltage voc. A solar cell, or photovoltaic cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon. Physical parameters of gaas and graphene used in simulation for schottky junction solar cells are listed in table 1. Highefficiency thinfilm ingapingaasge tandem solar cells. The silicon curve represents a 10 ohm cm textured cell with back surface field 5 while. All solar cells include the latest triple and quadruple junction technology, where gainp gaas ge layers are grown on a germanium substrate and the whole product range benefits from many years experience on the space market. The following is adapted from a masdar institute article by erica solomon.
Fourjunction waferbonded concentrator solar cells ieee. The single junction gaas based solar cells grown by mocvd were investigated in our lab since 1994. Gallium arsenide gaas is a compound of the elements gallium and arsenic. Highefficiency nanostructured window gaas solar cells. Unlike with a bulktype solar cell, optimizing photon management can enhance the collection efficiency of a thinfilm solar cell 20,21. Fabrication of high efficiency solar cells sc requires a. Gainpgaas dual junction solar cells on gesi epitaxial. The study of the behavior of solar cells with temperature t is important as, in terrestrial applications, they are generally exposed to temperatures ranging from 15 1c 288 k to 50 1c 323 k 1 and to even higher. Figure 1 shows a schematic diagram of a typical solar cell. A solar cell is an electronic device which directly converts sunlight into electricity. Since 2004 the investigations of gaas based solar cells grown in the aix 2004 reactor on n and p substrates have been carried out. Highly efficient cdsquantumdotsensitized gaas solar cells. Gaas wafers are preferred over silicon and other compound semiconductor devices because of better functionality, scalability, and compatibility with the iot network.
The n on p and p on n structures of dualjunction gainp gaas solar cell monolithic structures was grown by the mocvd technique. Gaas solar cells offer the highest efficiency demonstrated to date for space applications, with measured values exceeding 20% amo, 7. Considering this point, a solar cell covered with a pmma sws can be modeled as a solar cell covered with an infinite pmma medium, as shown in fig. Indium arsenide inas quantum dots in gallium arsenide gaas substrate.
They successfully obtained spectrally and spatially resolved photoluminescence pl images of a standard gaas solar cell from the fraunhofer institute for solar energy systems ise. Gaas solar cells on singlecrystal ge substrates have demonstrated efficiencies comparable to those on singlecrystal gaas substrates 6. Ringel, ohio state university mit subtier contractor ingap cell gaas cell graded sige. The high efficiency and radiation resistant gaas solar cells with internal bragg reflector were developed. Presented at the pv module reliability workshop, february 26 27 20, golden, colorado created date. The gaas thinfilm solar cell is a top contender in the thinfilm solar cell market in that it has a high power conversion efficiency pce compared to that of other thinfilm solar cells. Figure 2a shows a tiltview scanning electron microscope. The wider bandgap of the semiconductors used can increase the energy barrier for tunneling and thereby increase the resistance and lower the peak tunneling current for widebandgap tunnel junctions. This means that it can produce nearly twice as much power in a given surface area. The global gallium arsenide gaas wafer market is expected to grow at a cagr of 12. During simulation the thickness of gaas and graphene are taken as 10.
All solar cells include the latest triple and quadruple junction technology, where gainpgaasge layers are grown on a germanium substrate and the whole product range benefits from many years experience on the space. Antireflective coating gaas ge single junction solar cells. Some of the impediments to achieving a gaas backcontacted solar cell are the complex layered structure and the difficulties involved in doping gaas from external sources. Gaas is the highest performance solar material currently available, boasting conversion efficiencies in excess of 40%, nearly double those of crystalline silicon. Antireflection coatings for gaas solar cell applications. Highly efficient singlejunction gaas thinfilm solar cell. It is a iiiv direct band gap semiconductor with a zinc blende crystal structure gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monolithic microwave integrated circuits, infrared lightemitting diodes, laser diodes, solar cells and optical windows.
Characterization of production gaas solar cells for space 4. Silicon solar cells that possess all back contacts have been extensively explored 1,2. May 20, 2010 new method to make gallium arsenide solar cells. Because gaas substrates are somewhat fragile, the cell thickness must be appreciable 300 pm. Gainp gaas dual junction solar cells on gesi templates were fabricated using wafer bonding and.
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