A5035140041- ZnO doping and properties
- Spectroscopy and Laser Applications
- Semiconductor Quantum Structures and Devices
- Plasmonic and Surface Plasmon Research
- Gas Sensing Nanomaterials and Sensors
- Atmospheric Ozone and Climate
- Metamaterials and Metasurfaces Applications
- GaN-based semiconductor devices and materials
- Photonic Crystals and Applications
- Quantum Dots Synthesis And Properties
- Copper-based nanomaterials and applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Chalcogenide Semiconductor Thin Films
- solar cell performance optimization
- Random lasers and scattering media
- Thermal Radiation and Cooling Technologies
- Terahertz technology and applications
- Electronic and Structural Properties of Oxides
- Perovskite Materials and Applications
- Photovoltaic System Optimization Techniques
- Magnetic and transport properties of perovskites and related materials
- Optical Coatings and Gratings
- Ocular Surface and Contact Lens
- Semiconductor materials and devices
- Corneal Surgery and Treatments
Centro de Tecnologías Aeronauticas (Spain)
2024
Universidad Politécnica de Madrid
2016-2022
Institut für Sozialforschung und Sozialwirtschaft
2018
Universidad Complutense de Madrid
2017
We have developed a method to grow and characterize the state of art non-polar ZnO/(Zn,Mg)O multi-quantum wells on m-plane ZnO substrates as prerequisite for applications based intersubband transitions. The epilayer interfaces exhibit low roughness, layer thickness remains constant within one monolayer in these heterostructures. optical properties been studied UV IR domains by means photoluminescence absorption experiments, respectively. In UV, is very well described an excitonic transition,...
This paper reports on the demonstration of quantum cascade detectors (QCDs) based ZnO/ZnMgO wells (QWs) grown by molecular beam epitaxy an m-plane ZnO substrate. The TM-polarized intersubband absorption is peaked at a 3 μm wavelength. sample has been processed in form square mesas with sizes ranging from 10 × μm2 up to 100 μm2. I-V characteristics reveal that 86% 260 devices are operational and surface leakage current negligible room temperature, which not case 77 K. photocurrent...
Transparent conducting oxides (TCOs) are widely used in applications from solar cells to light emitting diodes. Here, we show that the metal organic chemical vapor deposition (MOCVD)-grown, rock-salt CdZnO ternary, has excellent potential as a TCO. To assess this compound, use combination of infrared reflectance and ultraviolet-visible absorption spectroscopies, together with Hall effect, determine its optical electrical transport characteristics. It is found incorporation Zn produces an...
The ZnO-based heterostructures are predicted to be promising candidates for optoelectronic devices in the infrared and terahertz (THz) spectral domains owing their intrinsic material properties. Specifically, large ZnO LO-phonon energy reduces thermally activated scattering, which is greatly improve temperature performance of THz quantum cascade lasers. However, date, no experimental observation intersubband emission from has been reported. Here, we report electroluminescence ZnO/MgxZn1–xO...
Unexpected light propagation effects, such as negative refraction, have been reported in artificial media. Leveraging on the intersubband resonances heterostructured semiconductors, we show that all possible optical regimes, ranging from classical dieletric and metal to hyperbolic metamaterial types 1 2, can be achieved. As a demonstration, prove refraction effect occur at designed frequency by controlling electronic quantum confinement.
Highly doped multiple quantum wells (MQWs) are significant for infrared optoelectronics, plasmonics, and the physics of strong light-matter coupling. The authors reveal a multisubband plasmon (MSP) that arises from couplings among several intersubband transitions in (Mg,Zn)O/ZnO MQWs, due to outstandingly dense two-dimensional electron gas. Here MSP energy is up three times constituent transitions, illustrating potential this system optoelectronic applications infrared, which could be...
The development of new nanophotonic devices requires the understanding and modulation propagating surface plasmon phonon modes arising in plasmonic polar dielectric materials, respectively. Here we explore CdZnO alloy as a material, with tunable plasma frequency reduced losses compared to pure CdO. By means attenuated total reflectance, experimentally observe hybridization polariton (SPP) (SPhP) air-CdZnO-sapphire three-layer system. We show how through precise control thickness, resonance...
Intersubband transitions in ZnO-based materials are predicted to be a promising basis for infrared and terahertz optoelectronic devices, particularly quantum cascade lasers. Utilizing nonpolar ZnO substrate optimizing growth conditions, the authors observe strong coupling between asymmetric ZnO/Mg${}_{x}$Zn${}_{1\ensuremath{-}x}$O wells. due high doping level heterostructures leads formation of multisubband plasmons. The results an important step toward realization ultrafast ZnO/MgxZn1-xO...
Abstract This paper proposes a methodology for assessing the concentrator solar cell reliability in real application given location provided results from accelerated life tests. We have applied this evaluation of warranty times commercial triple junction cells operating inside modules Golden (Colorado, USA), Madrid (Spain) and Tucson (Arizona, USA) period 2012–2015. Warranty Madrid, namely, 68 31 years, respectively, analysed period, indicate robustness cells. Nevertheless, time 15 years...
Abstract Metal-oxides hold promise as superior plasmonic materials in the mid-infrared compared to metals, although their integration over established material technologies still remains challenging. We demonstrate localized surface plasmons self-assembled, hemispherical CdZnO metal-oxide nanoparticles on GaAs, a route enhance absorption photodetectors. In this system, two plasmon modes are identified at 5.3 and 2.7 μm, which yield an enhancement of light intensity underlying GaAs. case...
The electrical and optical properties of m-plane Ga-doped ZnMgO alloys are analyzed by capacitance-voltage profiling, Hall effect, IR reflectance UV-VIS absorption spectroscopies, spanning more than four orders magnitude in electron concentration. Mg contents up to 50% achieved while maintaining the wurtzite phase, with a measured band-edge energy 4.41 eV. Despite deterioration incorporation, high concentrations (∼4.4×1019cm−3) for 35%, revealing doping efficiencies close 100%. potential...
Optoelectronic devices based on intersubband transitions (ISBT) typically require surface texturing after growth, to overcome the selection rules for polarization and operate under normally incident light. The authors demonstrate that $m$-plane ZnO/(Mg,Zn)O multiple quantum wells (QWs) self-assemble in a geometry allows absorption at normal incidence, depending state of light with respect $c$ axis. These QWs behave as self-assembled metamaterial, building block polarization-sensitive...
ZnO has great potential for devices in the mid IR and THz range through use of intersubband (ISB) transitions multiple quantum wells (MQWs), although exploiting these requires control epitaxial layers as well physics involved. In this work we present an analysis non-polar grown homoepitaxially by molecular beam epitaxy on m-plane substrates ISB optical absorber. The MQWs were characterized under a 45°-bevelled multi-pass waveguide configuration allowing observation at room temperature...
In a previous work the warranty time of commercial lattice-matched GaInP/Ga(In)As/Ge triple junction concentrator solar cells was evaluated under real climatic conditions. The had size 7x7 mm operating with an efficiency 35% at 820×. For these particular for three locations, Golden (CO-USA), Madrid (Spain), and Tucson (AZ-USA), exhibits 4 to 1 ratio, which affects LCOE (Levelized Cost Electricity) in important way. this work, we go step further evaluating influence concentration cell on...
Intersubband (ISB) polarons result from the interaction of an ISB transition and longitudinal optical (LO) phonons in a semiconductor quantum well (QW). Their observation requires very dense two dimensional electron gas (2DEG) QW polar or highly ionic semiconductor. Here we show that ZnO/MgZnO QWs strength such coupling can be as high 1.5 times LO-phonon frequency due to 2DEG achieved large difference between static high-frequency dielectric constants ZnO. The polaron is observed optically...
A method based on infrared reflectance spectroscopy is presented by which the Mg content in ZnO/(Zn,Mg)O multiple quantum wells with very thin barriers can be determined. The relies observation of interface phonon-polaritons appear as sharp dips p-polarized spectra at oblique incidence near longitudinal optical (LO)-phonon frequencies both QW and barrier materials. By fitting to a dielectric function model, LO phonon frequency (Zn,Mg)O layers depends content. Comparing calibration via...
In this work we show the potential of ZnO/ZnMgO material system for intersubband (ISB)-based devices. This family alloys presents a unique set properties that makes it highly attractive THz emission as well strong coupling regimes: has very large longitudinal optical phonon energy 72 meV, can be doped up to ~10<sup>21</sup> cm<sup>-3</sup>, is ionic with difference between static and high frequency dielectric constants, grown homoepitaxially on native substrates low defect densities. The...
Intersubband absorption at normal incidence is forbidden by the selection rules and requires oblique operation or texturing of surface intersubband-based devices such as focal plane arrays, adding additional processing steps to their fabrication therefore increasing complexity costs. Here we demonstrate normal-incidence, polarization sensitive intersubband wurtzite ZnO/MgZnO quantum wells grown on an m-plane orientation. When in this non-polar plane, spontaneously assemble forming a V-groove...
Transparent Conductive Oxides (TCOs) have been described as a promising alternative to metals for IR plasmonics. However, low propagation of surface plasmons is major shortcoming limiting the potential these materials in waveguiding-related applications. As proof concept, we propose using polar plasmonic substrates method overcome this issue. In study, demonstrate existence hybrid phonon-plasmon waves an air-CdZnO-sapphire system and characterize their properties, including improved distance...
We show here that Cd(Zn)O can be deposited on GaAs by MOCVD forming nanoparticles with a hemispherical shape. These maintain the key characteristics from CdO film: very high plasma frequency and low losses, hence retaining strong plasmonic character. As result of this, when illuminated infrared light, two localized surface plasmon (LSP) modes are excited at 2.7 5.3 microns, electric field is heavily amplified in underlying substrate. Moreover, their geometry allows them to partially change...
In this work we propose the use of self-assembled CdZnO nanoparticles as a route to improve power absorption in midinfrared GaAs-based quantum well infrared photodetectors (QWIPs). We experimentally demonstrate low temperature growth on GaAs and characterize their plasmonic response mid-IR. Computational analysis resonances coupled intersubband transitions wells show that at normal incidence, forbidden by selection rules, can be obtained. Gains high 5.5 are also reported.
Quantum cascade (QC) lasers opens new prospects for powerful sources operating at THz frequencies. Up to now the best QC are based on intersubband emission in GaAs/AlGaAs quantum well (QW) heterostructures. The maximum temperature is 200 K, which too low wide-spread applications. This due rather LO-phonon energy (36 meV) of GaAs-based materials. Indeed, thermal activation allows non-radiative path through electron-phonon interaction destroys population inversion. Wide band gap materials such...
The development of Zinc Oxide (ZnO)-based applications have been strongly limited due to the lack reproducible p-type doping. Here we present novel opportunities in field unipolar oxide wide band gap semiconductors. First developed growth nonpolar ZnO/ZnMgO multiple quantum wells (MQWs) and then demonstrate that structural optical properties MQWs are reaching required level for intersubband devices terms defects, surface interface roughness We will show discuss most recent results as,...