- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Toward >25% Efficient Monolithic Epitaxial GaAsP/Si Tandem Solar Cells
摘要： We report here on progress made in the development of >20% efficient monolithic epitaxial III-V/Si tandem solar cells. Following our prior demonstration of a GaAs0.75P0.25/Si tandem cell with verified AM1.5G efficiency of 20.1%, we have undertaken intensive efforts aimed at optimization of the top and bottom subcells, involving both materials quality improvement and detailed device structure refinement. To date we have thus demonstrated 21.8% AM1.5G GaAs0.75P0.25/Si tandem cells making use of an optimized, but still defect-limited GaAsP top cell combined with a simple diffusion-processed (emitter and back-surface field) Si bottom cell. With recent development of a low dislocation density III-V-on-Si epitaxial materials platform, as well as bottom cell enhancements for photon management, analytical performance loss analysis and efficiency projections indicate that >25% is achievable in the near-term, and 30% within reach with additional holistic optimization.
关键词： photovoltaic cells,Si,III-V semiconductor materials,semiconductor epitaxial layers
更新于2025-09-23 15:21:01
-
Galliuma??Borona??Phosphide ($$\hbox {GaBP}_{2}$$): a new IIIa??V semiconductor for photovoltaics
摘要： Using machine learning (ML) approach, we unearthed a new III–V semiconducting material having an optimal bandgap for high-efficient photovoltaics with the chemical composition of Gallium–Boron–Phosphide (GaBP2, space group: Pna21). ML predictions are further validated by state-of-the-art ab initio density functional theory simulations. The stoichiometric Heyd–Scuseria–Ernzerhof bandgap of GaBP2 is noted to be 1.65 eV, a close ideal value (1.4–1.5 eV) to reach the theoretical Queisser–Shockley limit. The calculated electron mobility is similar to that of silicon. Unlike perovskites, the newly discovered material is thermally, dynamically and mechanically stable. Above all the chemical composition of GaBP2 is non-toxic and relatively earth abundant, making it a new generation of PV material. Using ML, we showed that with a minimal set of features, the bandgap of III–III–V and II–IV–V semiconductor can be predicted up to an RMSE of less than 0.4 eV. We have presented a set of scaling laws, which can be used to estimate the bandgap of new III–III–V and II–IV–V semiconductor, with three different crystal phases, within an RMSE of 0.4 eV.
关键词： Gallium–Boron–Phosphide,photovoltaics,GaBP2,III–V semiconductor,density functional theory,machine learning
更新于2025-09-23 15:21:01
-
Investigation of the structural and electronic properties of InP1-xSbx alloy for mid-infrared optoelectronic applications: A TB-mBJ DFT study
摘要： The structural and electronic properties of InP1(cid:1)xSbx supercell structure at different percent of Sb incorporation have been studied under the Density Functional Theory formalism employing WIEN2K package. From the total energy calculations, the supercell lattice structures have been optimized. The structural properties have been calculated from the equation of state which suggests the supercell structures to be signi?cantly stable with a higher degree of compressive ?exibility (speci?cally, at lower percent of Sb incorporation). The contribution of the partial and total DOS (Density of States) of constituent elements to total DOS of the supercell structure has been investigated. The relativistic effects have been assimilated into the band structure calculation, along various high symmetry k directions for each supercell structure. The values obtained for band gap (both, direct and indirect), spin-orbit splitting energy and bowing coef?cient have been observed to vary signi?cantly as a function of Sb mole fraction. Moreover, a relationship has been established between band gap (both, direct and indirect) values and spin-orbit splitting energy with Sb mole fraction. The in?uence of SOC (spin-orbit coupling) effect on the parameters concerning electronic properties has also been analyzed. The effective mass values for conduction and valence sub-bands (heavy hole, light hole and spin orbit split-off hole) near the Brillouin zone has been calculated at different percent of Sb incorporation in InP1(cid:1)xSbx supercell structure. The interpretation of these results obtained suggests InP1(cid:1)xSbx material to be competent for mid-infrared optoelectronic applications.
关键词： III-V semiconductor,Electronic band structure,DOS,DFT calculation,Effective mass calculation,Structural and electronic property
更新于2025-09-23 15:21:01
-
High-Speed MOVPE Growth of InGaP Solar Cells
摘要： Impacts of reactor pressure and growth temperature on the qualities and properties of InGaP epitaxial layers grown in a narrow-channel horizontal metalorganic vapor-phase epitaxy (MOVPE) reactor were investigated with a growth rate of 10 μm/h. The roughness of InGaP was improved remarkably when the pressure was increased from 6 to 10 and 15 kPa. The reason is most likely related to the absolute pressure of P and the migrations of In and Ga adatoms on the wafer surface. Owing to the gas-phase reactions and desorption of P from InGaP, the surface of InGaP became rough, and the pit dislocation was increased with an increase in growth temperature. Although a low temperature was beneficial in order to obtain a smooth InGaP surface, the carrier lifetime in InGaP was shortened as a drawback. Consequently, InGaP n-on-p solar cells grown at a low temperature suffered from the degradations of both short-circuit current density and open-circuit voltage. Background impurities and defect densities in low temperature grown InGaP were attributed to these deteriorations. At the optimized growth temperature of 650 °C and the reactor pressure of 15 kPa, the growth rate of InGaP was accelerated to 20 and 30 μm/h. InGaP solar cells were successfully fabricated with the rate of 30 μm/h that opened up the way for the fabrication of III–V multijunction solar cells in the high-speed MOVPE reactor.
关键词： III–V semiconductor materials,semiconductor growth,photovoltaic cells
更新于2025-09-23 15:19:57
-
Review on III-V Semiconductor Single Nanowire-Based Room Temperature Infrared Photodetectors
摘要： Recently, III-V semiconductor nanowires have been widely explored as promising candidates for high-performance photodetectors due to their one-dimensional morphology, direct and tunable bandgap, as well as unique optical and electrical properties. Here, the recent development of III-V semiconductor-based single nanowire photodetectors for infrared photodetection is reviewed and compared, including material synthesis, representative types (under different operation principles and novel concepts), and device performance, as well as their challenges and future perspectives.
关键词： nanowire,III-V semiconductor,infrared photodetector
更新于2025-09-23 15:19:57
-
Absorption of light in a single vertical nanowire and a nanowire array
摘要： Both a single III–V semiconductor nanowire and an array of such nanowires have shown promise for solar cell applications. However, the correspondence between the optical properties of the single nanowire and the nanowire array has not been studied. Here, we perform electromagnetic modeling of InP nanowires to study this relationship. We find that a single nanowire can show at an absorption peak, a remarkably high absorption cross-section that is more than 50 times the geometrical cross-section. With optimization of the diameter of the single nanowire, the short-circuit current density is 30 times higher than in a bulk solar cell. With such a strong absorption, we predict an apparent efficiency >500% for the single nanowire solar cell. In contrast, we show that an efficient nanowire array solar cell cannot rely on strong absorption just through the absorption peak. Instead, the nanowires need to be packed rather closely to enhance the absorption of the full solar spectrum. At the optimum diameter for the nanowire array, neighboring nanowires compete strongly for absorption of incident photons at the absorption peak, which limits the absorption per nanowire by a factor of 18. As a result, the single InP nanowire is optimized at a diameter of 110 nm while the nanowires in the array are optimized at a considerably larger diameter of 180 nm. Importantly, we show analytically the coupling efficiency of incident light into the fundamental HE11 guided mode and consecutive absorption of the mode in the nanowires. With that analysis, we explain that a single nanowire shows two different absorption pathways—one through coupling into the guided mode and another by coupling into the nanowire through the sidewall. This analytical analysis also shows at which period the neighboring nanowires in an array start to compete for absorption of incident photons.
关键词： III–V semiconductor nanowire,optics modeling,absorption,solar cell
更新于2025-09-19 17:15:36
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Investigating Industrial Metallization Solutions for Double-side Contact Passivated biPoly Solar Cells
摘要： We present the design and fabrication of suspended optical waveguides on indium phosphide platform for use in an optical buffer device with MEMS actuation, in which the optical delay can be achieved by changing the spacing of the waveguides by electrostatic actuation. The optical and mechanical properties of the waveguides and pillar supports are modeled, and different MEMS actuation schemes are simulated. We also present fabrication and characterization results of the epitaxially grown sample structure and of the suspended waveguide device, exhibiting two parallel waveguides with submicron dimensions separated by a 400-nm air gap, and suspended at 40-μm intervals by S-shaped supports.
关键词： microelectromechanical systems,indium phosphide,optical waveguides,III-V semiconductor materials,optical buffering
更新于2025-09-19 17:13:59
-
Investigation of Rear-Emitter GaAs <sub/>0.75</sub> P <sub/>0.25</sub> Top Cells for Application to III–V/Si Tandem Photovoltaics
摘要： A rear-emitter (rear-junction) n-on-p+ device design was investigated for use in metamorphic monolithic III–V/Si tandem solar cells as an alternative to the traditional front-emitter (front-junction) n+-on-p design for potentially greater resistance to threading dislocation-induced performance degradation. A comparison of MOCVD-grown rear- versus front-emitter 1.7-eV bandgap GaAs0.75P0.25 top cell isotypes demonstrated as 30-mV advantage in WOC for the rear-emitter design. This reduction in WOC was determined to be nearly equally caused by a reduction in junction recombination current as well as reduced reverse saturation current from improved quasi-neutral region transport. These results suggest that the rear-emitter design may indeed be a promising pathway for application to metamorphic cells, including III–V/Si tandems, where achieving maximum voltage output is often hindered by elevated dislocation densities. However, further optimization of short-circuit current collection is needed to overcome suboptimal collection probability pro?les that could limit the ef?cacy of such structures.
关键词： semiconductor epitaxial layers,photovoltaic (PV),photovoltaic cells,III–V semiconductor materials
更新于2025-09-12 10:27:22
-
Ion irradiation of III–V semiconductor surfaces: From self-assembled nanostructures to plasmonic crystals
摘要： Ion-irradiation of semiconductor surfaces has emerged as a promising approach to generate a variety of self-organized nanostructures. Furthermore, the combination of focused-ion-irradiation with molecular-beam epitaxy provides unprecedented design and control of surfaces and interfaces of hybrid materials at the atomic level during fabrication. In this review, we describe the directed self-assembly of nanostructure arrays ranging from islands to nanorods to 3-dimensional nanoparticle (NP) arrays. First, we discuss focused-ion-irradiation of III–V surfaces, which leads to preferential sputtering of group V species, followed by the formation of group III-rich metallic nanostructures. For continued irradiation beyond a threshold dose, the nanoparticle (NP) evolution is determined by the sputtering yield and the local ion beam angle of incidence, resulting in arrays of nanoparticles, nanorods, or nanoparticle chains. In addition to describing the formation of close-packed embedded Ga:GaAs nanocomposites using overgrowth of focused-ion-beam fabricated NP arrays, we discuss the surface plasmon resonances of NP arrays as well as the influence of both surface and buried NP arrays on the GaAs photoluminescence efficiency. Finally, we discuss the potential of “plasmonic crystals” for plasmon-enhanced optoelectronics.
关键词： self-assembled nanostructures,ion irradiation,plasmonic crystals,molecular-beam epitaxy,III-V semiconductor,nanoparticle arrays,surface plasmon resonances,photoluminescence efficiency,focused-ion-beam
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Ultrafast All-Optical Switching in III-V Semiconductor Resonant Nanostructures
摘要： All-dielectric high-index resonant nanostructures offer plentiful opportunities for tailoring characteristics of scattered radiation. In fact, the low level of ohmic losses at optical frequencies and the presence of pronounced magneto-dipolar modes in scattering spectra of dielectric nanoresonators pave the way to numerous scattering effects that could be employed for many practical applications [1]. To further advance the performance of dielectric nanophotonic devices, it is crucial to make them reconfigurable, i.e. to provide a method to manipulate optical properties of the material that they are made of. The electron-hole injection, carried out by optical means, is a promising solution for this task (Fig. 1A). Direct-gap semiconductors are perfectly suitable for that purpose, because this class of materials retains advantages typical for dielectrics and, at the same time, is defined by smaller bandgap widths, compared to dielectrics. The latter feature significantly decreases a value of the pumping pulse fluence that is required to noticeably change the optical response of a resonant nanostructure. Indeed, it was numerically shown that the change of the trajectory of the probing pulse constituted 20° for an asymmetric dimer comprised of two silicon (Si) spheres of different radii for the energy fluence of the pumping pulse Φ(cid:3020)(cid:3036) = 1.6 mJ cm(cid:2879)(cid:2870) [2]. On the other hand, there is an experimental study of all-optical switching in gallium arsenide (GaAs) metasurface that indicated the change of its reflection coefficient ?(cid:1844) = 0.35 for the fluence Φ(cid:3008)(cid:3028)(cid:3002)(cid:3046) = 0.31 mJ cm(cid:2879)(cid:2870) [3]. Although there are already some numerical results on the light scattering in the asymmetric dimer, it is still urgent to carry out the corresponding experiment. For that purpose, it is important to change the geometry of the system (cylinders instead of spheres) and its material (GaAs in place of Si). The system has an asymmetric scattering profile in the regular regime owing to its asymmetric geometry. The geometry also stipulates the difference in absorption cross-sections of the cylindrical resonators. Because of this difference in absorption, the change of the material’s optical parameters is not equal for the two cylinders. Therefore, under certain conditions, after the pumping of the nanostructure, the scattering diagram becomes symmetric. Our numeric results demonstrate the symmetrization of the indicatrix for the pumping fluence Φ(cid:2869) = 0.9 mJ cm(cid:2879)(cid:2870) (the corresponding change of the probe scattering direction was calculated to be 7°) for the dimer with following geometrical parameters: radii – 85 nm and 90 nm, height – 200 nm, distance between the centers of the disks – 450 nm. The central wavelength of the pulse spectrum was (cid:2019)(cid:2869) = 820 nm. The dimer nanoantenna is an ultrafast optical switch that can be used, for instance, to distribute optical signals between two waveguides in integrated photonic circuits. The design of the switch makes its fabrication compatible with modern technological methods. The all-optical modulation can be observed not only in single asymmetric nanoantennas, but also in phased-array metasurfaces composed of supercells with resonators of the different size. In particular, we considered a metasurface that could control the intensities (i.e. transmission coefficients) in the diffraction orders that are formed after the scattering on the nanostructure. In our experiments, the most pronounced relative change of the transmission coefficient was detected in the first order: ?(cid:1846) (cid:1846) = 9.7% for the fluence of the pumping pulse Φ(cid:2870) = 0.02 mJ cm(cid:2879)(cid:2870) (Fig. 2B). The metasurfaces of that kind can also be used as all-optical switches.
关键词： ultrafast optics,resonant nanostructures,III-V semiconductor,all-optical switching
更新于2025-09-12 10:27:22