A5033560436- Semiconductor Quantum Structures and Devices
- Silicon and Solar Cell Technologies
- solar cell performance optimization
- Semiconductor materials and interfaces
- Quantum Dots Synthesis And Properties
- Thin-Film Transistor Technologies
- Nanowire Synthesis and Applications
- Optical Coatings and Gratings
- Photonic and Optical Devices
- Chalcogenide Semiconductor Thin Films
- Near-Field Optical Microscopy
- Silicon Nanostructures and Photoluminescence
- Photovoltaic System Optimization Techniques
- Quantum and electron transport phenomena
- Thermal Radiation and Cooling Technologies
- Photonic Crystals and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor Lasers and Optical Devices
- Plasmonic and Surface Plasmon Research
- Photovoltaic Systems and Sustainability
- Advanced Thermodynamics and Statistical Mechanics
- Laser Design and Applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced Fiber Laser Technologies
- Advancements in Semiconductor Devices and Circuit Design
Universidad Politécnica de Madrid
2008-2020
European Telecommunications Standards Institute
2002-2007
IMDEA Energy Institute
1991-2007
Yazaki (Japan)
2005
Comunidad de Madrid
1999-2005
Optica
1967-1969
Rutgers, The State University of New Jersey
1965
In order to enhance infrared light absorption in sub-bandgap transitions an intermediate band solar cell, the scattered near-field potential from uncoated and coated metallic nanoparticles with a spheroidal shape is calculated electrostatic model. The enhancement produced at surface plasmon frequency of can be several orders magnitude some cases.
Abstract The application of diffraction gratings to solar cells is a promising approach superseding the light trapping limits conventional Lambertian structures. In this paper mathematical formalism derived for calculating absorption that can be expected in cell equipped with grating, which applied any lattice geometry and grating profile. Furthermore, used calculate upper limit total theoretically achieved using grating. are valid when thickness greater than coherence length illuminating...
A colloidal deposition technique is presented to construct long-range ordered hybrid arrays of self-assembled quantum dots and metal nanoparticles. Quantum are promising for novel opto-electronic devices but, in most cases, their optical transitions interest lack sufficient light absorption provide a significant impact implementation. potential solution couple the with localized plasmons The extreme confinement near-field produced by nanoparticles can potentially boost up two orders...
Light trapping is becoming of increasing importance in crystalline silicon solar cells as thinner wafers are used to reduce costs.In this work, we report on light by rear-side diffraction gratings produced nano-imprint lithography using interference the mastering technology.Gratings fabricated shown provide significant absorption enhancements.Through a combination optical measurement and simulation, it that crossed grating provides better enhancement than linear grating, parasitic reflector...
This paper presents a numerical study of the light focusing properties dielectric spheroids with sizes comparable to illuminating wavelength.An analytical separation-of-variables method is used determine electric field distribution inside and in near-field outside particles.An optimization algorithm was implemented particles' physical parameters that maximize forward scattered region.It found such scatterers can exhibit pronounced intensity enhancement (above 100 times incident intensity)...
In this paper, a model for intermediate band solar cells is built based on the generally understood physical concepts ruling semiconductor device operation, with special emphasis behavior at low temperature. The compared to JL-VOC measurements concentrations up about 1000 suns and temperatures down 20 K, as well of radiative recombination obtained from electroluminescence. agreement reasonable. It found that main reason reduction open circuit voltage an operational bandgap, but effect...
Abstract Two‐terminal, monolithic tandem solar cells represent the most interesting implementation of tThe multijunction photovoltaic array capable very high efficiency. Radiative coupling among cells, and between substrate, along with series interconnection are features present in this approach. Their effect on efficiency is quantified for arrays a small number radiative limit compared best experimental to assess their potential improvement. Finally, it shown that they do not lower limiting...
A simplified three-dimensional study is presented of the light confinement, that is, enhancement Poynting vector electromagnetic radiation inside a solar cell absorbing weakly when diffracting structures are used. The model based on theory periodic arrays and easily applied to one- two-dimensional diffraction gratings. Realistically wide illumination bundles considered. extended nature severely limits capabilities structures. Results compared those more widely used Lambertian confinement.
ABSTRACT In this paper, we present calculations of the absorption coefficient for transitions between bound states quantum dots grown within a semiconductor and extended conduction band. For completeness, among are also presented. separation variables, single band k·p model is used in which most elements may be expressed analytically. The analytical formulae collected appendix paper. It concluded that strong enough to provide quick path electrons pumped from valence intermediate Copyright ©...
We present a theoretical study of electric field scattering by wavelength-sized spheroids. The incident, internal, and scattered fields are computed analytically spheroidal coordinate separation-of-variables solution, assuming axially incident monochromatic illumination. main sources possible numerical errors identified an additional point-matching procedure is implemented to provide built-in test the validity results. Numerical results were obtained for prolate oblate particles with...
The effect of quantum dot (QD) size on the performance intermediate band solar cells is investigated. A numerical model used to calculate bound state energy levels and absorption coefficient transitions from ground all other states in conduction band. Comparing with current art, strong enhancements are found for smaller dots, as well a better positioning levels, which expected reduce thermal carrier escape. It concluded that reducing can increase sub-bandgap photocurrent improve voltage preservation.
The concept of intermediate band solar cell (IBSC) is, apparently, simple to grasp. However, since the idea was proposed, our understanding has improved and some concepts can now be explained more clearly than when initially introduced. Clarifying these is important, even if they are well known for advanced researcher, so that research efforts driven in right direction from start. six pieces this work are: Does a miniband need formed IBSC implemented with quantum dots? What problems each...
Textured silicon solar cells have been generally studied in the geometrical optics approximation. This description predicts no dependence of reflectance or other optical properties on size texture pyramids. In this work textures are represented as two-dimensional periodic diffraction gratings and their analyzed with rigourous numerical methods. It is concluded that significantly increases respect to limit for pyramid sizes smaller than around 300 nm. Besides, small pyramids light transmitted...
To achieve high efficiency, the intermediate band (IB) solar cell must generate photocurrent from sub-bandgap photons at a voltage higher than that of single contributing photon. latter, it is necessary IB levels be properly isolated valence and conduction bands. We prove this not case for cells formed with confined InAs quantum dots (QDs) in GaAs grown so far due to strong density internal thermal transition energies involved. counteract this, QD smaller.