Showing papers on "Quantum well published in 2003"
TL;DR: In this paper, the authors provide a critical summary of some recent developments of new concepts and new materials in thermoelectric materials research, including quantum wells, superlattices, quantum wires, and quantum dots.
Abstract: Efficient solid state energy conversion based on the Peltier effect for cooling and the Seebeck effect for power generation calls for materials with high electrical conductivity σ, high Seebeck coefficient S, and low thermal conductivity k. Identifying materials with a high thermoelectric figure of merit Z(= S2σ/k) has proven to be an extremely challenging task. After 30 years of slow progress, thermoelectric materials research experienced a resurgence, inspired by the developments of new concepts and theories to engineer electron and phonon transport in both nanostructures and bulk materials. This review provides a critical summary of some recent developments of new concepts and new materials. In nanostructures, quantum and classical size effects provide opportunities to tailor the electron and phonon transport through structural engineering. Quantum wells, superlattices, quantum wires, and quantum dots have been employed to change the band structure, energy levels, and density of states of elect...
932 citations
TL;DR: In this article, the first energy transition 1h − 1e as a function of x and the well width was calculated for cubic AlxGa1−xN/GaN/AlxGa 1 −xN quantum wells and the nearest neighbor sp 3 s ∗ empirical tight binding approximation, together with the Surface Green Function Matching method was used.
Abstract: For cubic AlxGa1−xN/GaN/AlxGa1−xN quantum wells we calculated the first energy transition 1h–1e as a function of x and the well width. The nearest neighbour sp 3 s ∗ empirical tight binding approximation, including spin-orbit interaction, together with the Surface Green Function Matching method is used.
543 citations
TL;DR: In this article, a quantum cascade laser at λ=87.2 µm was developed for electron depopulation at 3.44 THz and 14.2 meV photon energy.
Abstract: We report the development of a quantum cascade laser, at λ=87.2 μm, corresponding to 3.44 THz or 14.2 meV photon energy. The GaAs/Al0.15Ga0.85As laser structure utilizes longitudinal-optical (LO) phonon scattering for electron depopulation. Laser action is obtained in pulsed mode at temperatures up to 65 K, and at 50% duty cycle up to 29 K. Operating at 5 K in pulsed mode, the threshold current density is 840 A/cm2, and the peak power is approximately 2.5 mW. Based on the relatively high operating temperatures and duty cycles, we propose that direct LO-phonon-based depopulation is a robust method for achieving quantum cascade lasers at long-wavelength THz frequencies.
411 citations
TL;DR: In this article, a GaAs/AlxGa(1−x)As quantum well laser has been demonstrated via organometallic chemical vapor deposition on relaxed graded Ge/GeSi/Si virtual substrates on Si.
Abstract: GaAs/AlxGa(1−x)As quantum well lasers have been demonstrated via organometallic chemical vapor deposition on relaxed graded Ge/GexSi(1−x) virtual substrates on Si. A number of GaAs/Ge/Si integration issues including Ge autodoping behavior in GaAs, reduced critical thickness due to thermal expansion mismatch, and complications with mirror facet cleaving have been overcome. Despite unoptimized laser structures with high series resistance and large threshold current densities, surface threading dislocation densities for GaAs/AlGaAs lasers on Si substrates as low as 2×106 cm−2 permitted continuous room-temperature lasing at a wavelength of 858 nm. The laser structures are uncoated edge-emitting broad-area devices with differential quantum efficiencies of 0.24 and threshold current densities of 577 A/cm2. Identical devices grown on commercial GaAs substrates showed similar behavior. This comparative data agrees with previous measurements of near-bulk minority carrier lifetimes in GaAs grown on Ge/GeSi/Si substrates.
301 citations
TL;DR: In this article, the authors demonstrate simultaneous lasing at two well-separated wavelengths in self-assembled InAs quantum-dot lasers via ground state (GS) and excited state (ES) transitions.
Abstract: We demonstrate simultaneous lasing at two well-separated wavelengths in self-assembled InAs quantum-dot lasers, via ground-state (GS) and excited-state (ES) transitions. This effect is reproducible and strongly depends on the cavity length. By a master-equation model, we attribute it to incomplete clamping of the ES population at the GS threshold.
291 citations
23 Jan 2003
TL;DR: In this paper, the authors introduce the theory of OPTICAL PROCESSES and its application in two-dimensional (2D) systems and demonstrate the effects of electrics on low-dimensional (low-DIMENSIONal) systems.
Abstract: 1 INTRODUCTION 2 CLASSICAL THEORY OF OPTICAL PROCESSES 3 PHOTONS 4 ELECTRON BAND STRUCTURE AND ITS MODIFICATIONS 5 INTERBAND AND IMPURITY ABSORPTIONS 6 EXCITONIC ABSORPTION 7 ABSORPTION AND REFRACTION IN AN ELECTRIC FIELD 8 INTERBAND MAGNETO-OPTICAL EFFECTS 9 FREE CARRIER PROCESSES 10 RECOMBINATION PROCESSES 11 INTRODUCTION TO TWO-DIMENSIONAL SYSTEMS 12 OPTICAL PROCESSES IN QUANTUM WELLS 13 EXCITONS AND IMPURITIES IN QUANTUM WELLS 14 OPTICAL PROCESSES IN QUANTUM WIRES AND DOTS 15 SUPERLATTICES 16 STRAINED LAYERS 17 EFFECTS OF ELECTRIC FIELD ON LOW DIMENSIONAL SYSTEMS
289 citations
TL;DR: In this paper, a novel quantum-wire-in-optical-fiber (Qwof) nanostructure was obtained as a result of spontaneous Al−Ga−N phase separation at the nanometer scale in one dimension.
Abstract: Quantum wire lasers are generally fabricated through complex overgrowth processes with molecular beam epitaxy. The material systems of such overgrown quantum wires have been limited to Al−Ga−As−P, which leads to emission largely in the visible region. We describe a simple, one-step chemical vapor deposition process for making quantum wire lasers based on the Al−Ga−N system. A novel quantum-wire-in-optical-fiber (Qwof) nanostructure was obtained as a result of spontaneous Al−Ga−N phase separation at the nanometer scale in one dimension. The simultaneous excitonic and photonic confinement within these coaxial Qwof nanostructures leads to the first GaN-based quantum wire UV lasers with a relatively low threshold.
285 citations
TL;DR: In this paper, high-resolution TEM images acquired immediately after first irradiating a region of quantum well indicates no gross fluctuations of indium content in the InGaN alloy, during only a brief period of irradiation, inhomogeneous strain is introduced in the material due to electron beam damage.
Abstract: InGaN quantum wells have been found to be extremely sensitive to exposure to the electron beam in the transmission electron microscope (TEM). High-resolution TEM images acquired immediately after first irradiating a region of quantum well indicates no gross fluctuations of indium content in the InGaN alloy. During only a brief period of irradiation, inhomogeneous strain is introduced in the material due to electron beam damage. This strain is very similar to that expected from genuine nanometer-scale indium composition fluctuations which suggests there is the possibility of falsely detecting indium-rich “clusters” in a homogeneous quantum well.
258 citations
08 Jun 2003
TL;DR: In this paper, the fabrication, operation, and performance of quantum cascade lasers operating at far-infrared (terahertz) frequencies have been reviewed and compared. And the authors indicate recent results in which devices have been developed to operate continuous wave, at temperatures greater than 77 K, emit at frequencies down to 3.5 THz and produce tens of milli-Watts of power.
Abstract: Quantum cascade lasers operating at far-infrared (terahertz) frequencies have now been demonstrated. We review the fabrication, operation, and performance of these lasers, and indicate recent results in which devices have been developed to operate continuous wave, at temperatures greater than 77 K, emit at frequencies down to 3.5 THz, and produce tens of milli-Watts of power. These results are an encouraging step towards a widely applicable solid-state terahertz source, and the development of terahertz photonics.
225 citations
TL;DR: These studies illustrate that many-particle interactions, which are inherent in semiconductors and are often detrimental to quantum coherences, can also be harnessed to manipulate these coherence levels.
Abstract: We report an experimental demonstration and theoretical analysis of electromagnetically induced transparency in a GaAs quantum well, in which the absorption of an exciton resonance is reduced by more than twentyfold. The destructive quantum interference in this scheme is set up by a control pulse that couples to a resonance of biexcitons. These studies illustrate that many-particle interactions, which are inherent in semiconductors and are often detrimental to quantum coherences, can also be harnessed to manipulate these coherences.
194 citations
TL;DR: In this article, optical absorption and electro absorption studies on the lead-iodide-based natural quantum-well perovskite-type crystals with different well width (C6H13NH3)2(CH3NH3),m−1PbmI3m+1 with decreasing well thickness, m, the resonance energies of the lowest energy excitons shift to higher energy due to the increase of the bandgap.
TL;DR: In this paper, the structural and optical properties of GaAs-based 1.3 μm InAs/InGaAs dots-in-a-well (DWELL) structures have been optimized in terms of different InGaAs and GaAs growth rates, the amount of InAs deposited, and In composition of the INGaAs quantum well (QW).
Abstract: The structural and optical properties of GaAs-based 1.3 μm InAs/InGaAs dots-in-a-well (DWELL) structures have been optimized in terms of different InGaAs and GaAs growth rates, the amount of InAs deposited, and In composition of the InGaAs quantum well (QW). An improvement in the optical efficiency is obtained by increasing the growth rate of the InGaAs and GaAs layers. A transition from small quantum dots (QDs), with a high density (∼5.3×1010 cm−2) and broad size distribution, to larger quantum dots with a low dot density (∼3.6×1010 cm−2) and narrow size distribution, occurs as the InAs coverage is increased from 2.6 to 2.9 monolayers. The room-temperature optical properties also improve with increased InAs coverage. A strong dependence of the QD density and the QD emission wavelength on the In composition of InGaAs well has been observed. By investigating the dependence of the dot density and the high-to-width ratio of InAs islands on the matrix of InGaAs strained buffer layer (SBL), we show that the increasing additional material from wetting layer and InGaAs layer into dots and the decreasing repulsive strain field between neighboring islands within substrate are responsible for improving QD density with increasing In composition in InGaAs SBL. The optical efficiency is sharply degraded when the InGaAs QW In composition is increased from 0.15 to 0.2. These results suggest that the optimum QW composition for 1.3 μm applications is ∼15%. Our optimum structure exhibits a room temperature emission of 1.32 μm with a linewidth of 27 meV.
TL;DR: In this paper, the effect of spin-orbit coupling on the electrical conductivity in the presence of fixed impurity scatterers was studied and an exact solution of the two-dimensional Boltzmann equation was proposed.
Abstract: In a two-dimensional electron gas as realized by a semiconductor quantum well, the presence of spin-orbit coupling of both the Rashba and Dresselhaus type leads to anisotropic dispersion relations and Fermi contours. We study the effect of this anisotropy on the electrical conductivity in the presence of fixed impurity scatterers. The conductivity also shows in general an anisotropy which can be tuned by varying the Rashba coefficient. This effect provides a method of detecting and investigating spin-orbit coupling by measuring spin-unpolarized electrical currents in the diffusive regime. Our approach is based on an exact solution of the two-dimensional Boltzmann equation and provides also a natural framework for investigating other transport effects including the anomalous Hall effect.
TL;DR: Electromagnetically induced transparency in the transient optical response in a GaAs quantum well is demonstrated by using the nonradiative coherence between the heavy-hole and the light-hole valence bands.
Abstract: We demonstrate electromagnetically induced transparency in the transient optical response in a GaAs quantum well by using the nonradiative coherence between the heavy-hole and the light-hole valence bands
TL;DR: In this article, the authors show that a quantum well placed at an optimum distance from the mirror provides a ∼2.3× increase in total light output as compared to a QW placed at a neighboring position corresponding to a minimum in overall light extraction.
Abstract: Optical cavity effects have a significant influence on the extraction efficiency of InGaN/GaN quantum-well-heterostructure flip-chip light-emitting diodes (FCLEDs). Light emitted from the quantum well (QW) self-interferes due to reflection from a closely placed reflective metallic mirror. The interference patterns couple into the escape cone for light extraction from the FCLED. This effect causes significant changes in the extraction efficiency as the distance between the QW and the metallic mirror varies. In addition, the radiative lifetime of the QW also changes as a function of the distance between the QW and the mirror surface. Experimental results from packaged FCLEDs, supported by optical modeling, show that a QW placed at an optimum distance from the mirror provides a ∼2.3× increase in total light output as compared to a QW placed at a neighboring position corresponding to a minimum in overall light extraction.
TL;DR: In this paper, optical absorption and photocurrent measurements on a GaN/AlN-based superlattice were reported, where the photocurrent peak was slightly blueshifted (710 meV/5670 cm−1) and had a narrower width of 115 meV.
Abstract: We report optical absorption and photocurrent measurements on a GaN/AlN-based superlattice. The optical absorption has a full width at half maximum of 120 meV and takes place at an energy of 660 meV (5270 cm−1); this corresponds to a wavelength of 1.9 μm. While the optical absorption remained unchanged up to room temperature, the photocurrent signal could be observed up to 170 K. With respect to the optical absorption, the photocurrent peak was slightly blueshifted (710 meV/5670 cm−1) and had a narrower width of 115 meV. Using this quantum-well infrared photodetector, we were able to measure the spectrum of a 1.55 μm superluminescent light-emitting diode.
TL;DR: In this article, an overview of the properties of In x Ga 1-x N epilayers based on a systematic study of thick layers and of quantum well structures is presented.
Abstract: The In x Ga 1-x N system has electronic band gaps extending from under 1eV to 3.4 eV, and as such they are used as the active layer in commercially available visible-light emitting devices. There are many interesting features that make these nitride semiconductor alloys especially useful for efficient light emitters. It has been conjectured that the combination of piezoelectric fields and local composition inhomogeneities may be responsible for the observed high emission efficiencies, in spite of their characteristic high dislocation densities. But it is very difficult to grow In x Ga 1-x N layers with high indium composition. This paper presents an overview of the properties of In x Ga 1-x N epilayers based on a systematic study of thick layers and of quantum well structures. We find that the microstructure of thick films varies significantly with indium composition. For x 0.20, spontaneous phase separation occurs resulting in a polycrystalline, inhomogeneous layer. A correlation between optical properties and microstructure is presented. It is observed that the misfit strain is affected by threading dislocations. Mechanisms of misfit strain relaxation are presented for In x Ga 1-x N layers grown on standard GaN on sapphire and on epitaxial-lateral-overgrowth GaN layers. In addition, we have studied the properties of quantum well structures using several novel techniques. The electrostatic fields across the wells have been profiled using electron holography in the TEM. The effect of well thickness on the strength of the fields is reported. The effects of localization by compositional fluctuations and of internal field screening have been studied using time-resolved cathodoluminescence spectroscopy. In spite of significant progress that has been made in the last ten years, much work remains ahead in order to master the science and technology of these alloys.
TL;DR: These experiments report on experiments in which a spin-polarized current is injected from a GaMnAs ferromagnetic electrode into a GaAs layer through an AlAs barrier, and discuss the conditions on the hole spin relaxation time in GaAs that are required to obtain the large effects.
Abstract: We report on experiments in which a spin-polarized current is injected from a GaMnAs ferromagnetic electrode into a GaAs layer through an AlAs barrier. The resulting spin polarization in GaAs is detected by measuring how the tunneling current, to a second GaMnAs ferromagnetic electrode, depends on the orientation of its magnetization. Our results can be accounted for by sequential tunneling with the nonrelaxed spin splitting of the chemical potential, that is, spin accumulation, in GaAs. We discuss the conditions on the hole spin relaxation time in GaAs that are required to obtain the large effects we observe.
Book•
01 Jan 2003
TL;DR: The need for compact blue-green lasers is discussed in this article, where the upconversion of a single-pass second-harmonic generation and sum-frequency mixing are discussed.
Abstract: 1. The need for compact blue-green lasers Part I. Blue-green Lasers Based on Nonlinear Frequency Conversion: 2. Fundamentals of nonlinear frequency upconversion 3. Single-pass second-harmonic generation and sum-frequency mixing 4. Resonator-enhanced second-harmonic generation 5. Intracavity second-harmonic and sum-frequency generation 6. Guided-wave second-harmonic generation Part II. Upconversion Lasers: Physics and Devices: 7. Essentials of upconversion laser physics 8. Upconversion lasers Part III. Blue-green Semiconductor Lasers: 9. Introduction to blue-green semiconductor lasers 10. Device design, performance, and physics of optical gain of the InGaN quantum well violet diode lasers 11. Prospects and properties for vertical cavity blue light emitters 12. Concluding remarks Index.
TL;DR: In this article, a spin transistor using only non-magnetic materials was proposed to exploit the characteristics of bulk inversion asymmetry (BIA) in (110) symmetric quantum wells.
Abstract: We propose a spin transistor using only non-magnetic materials that exploits the characteristics of bulk inversion asymmetry (BIA) in (110) symmetric quantum wells. We show that extremely large spin splittings due to BIA are possible in (110) InAs/GaSb/AlSb heterostructures, which together with the enhanced spin decay times in (110) quantum wells demonstrates the potential for exploitation of BIA effects in semiconductor spintronics devices. Spin injection and detection is achieved using spin-dependent resonant interband tunneling and spin transistor action is realized through control of the electron spin lifetime in an InAs lateral transport channel using an applied electric field (Rashba effect). This device may also be used as a spin valve, or a magnetic field sensor. The electronic structure and spin relaxation times for the spin transistor proposed here are calculated using a nonperturbative 14-band k.p nanostructure model.
TL;DR: In this article, a drift diffusion model was proposed to explain the sublinear light-current characteristics and temperature dependence by the influence of the large acceptor ionization energy in Mg-doped GaN and a triangular density of states function characteristic of localized states.
Abstract: Pulsed light–current characteristics of InGaN/GaN quantum welllight-emitting diodes have been measured as a function of temperature, with sublinear behavior observed over the whole temperature range, 130–330 K. A distinctive temperature dependence is also noted where the light output, at a fixed current, initially increases with temperature, before reaching a maximum at 250 K and then decreases with subsequent increases in temperature. On the basis of a drift diffusion model, we can explain the sublinear light–current characteristics and the temperature dependence by the influence of the large acceptor ionization energy in Mg-doped GaN together with a triangular density of states function characteristic of localized states. Without the incorporation of localization effects, we are unable to reproduce the temperature dependence whilst maintaining emission at the observed wavelength. This highlights the importance of localization effects on device performance.
TL;DR: In this article, the equation of motion for the p-polarization field in an arbitrary wurtzite multilayer heterostructure is solved exactly for the interface optical-phonon modes.
Abstract: Based on the dielectric-continuum model and Loudon's uniaxial crystal model, the equation of motion for the p-polarization field in an arbitrary wurtzite multilayer heterostructure is solved exactly for the interface optical-phonon modes The polarization eigenvector, the dispersion relation, and the electron\char21{}interface-phonon interaction Fr\"ohlich-like Hamiltonian are derived using the transfer-matrix method The analytical formulas can be directly applied to single heterojunctions, single and multiple quantum wells (QW's), and superlattices Considering the strains of QW structures and the anisotropy effects of wurtzite crystals, the dispersion relations of the interface phonons and the electron\char21{}interface-phonon coupling strengths are investigated for GaN/AlN single and coupled QW's We find that there are four (eight) interface optical-phonon branches with definite symmetry with respect to the symmetric center of a single (coupled) QW Typical features in the dispersion curves are evidenced which are due to the anisotropy effects of wurtzite crystals The lower-frequency modes are much more important for the electron\char21{}interface-phonon interactions than the higher-frequency modes For the lower-frequency interface phonons, the intensity of the electron-phonon interactions is reduced due to the strain effects of the QW structures For the higher-frequency interface modes, the influence of the strains on the electron-phonon interactions can be ignored
TL;DR: In this article, the authors report the fabrication of optically-pumped solid-state distributed feedback lasers utilizing two blue-light-emitting semiconducting polyfluorenes as gain media.
Abstract: We report the fabrication of optically-pumped solid-state distributed feedback lasers utilizing two blue-light-emitting semiconducting polyfluorenes as gain media. The lasers were readily fabricated by solution deposition of thin polymer films on top of gratings etched into fused silica substrates. A compact Nd:YVO4 microchip laser was used as the pump source for the two polymers studied, and lasing was achieved at 455 and 465 nm. Low threshold energies, ⩾4 nJ per pulse, were obtained. The emission characteristics of the lasers are described along with the results of additional experiments that investigate in more detail the effect of the grating microstructure on polymer light emission.
TL;DR: In this paper, the authors compared near field and beam quality measurements on narrow stripe quantum-dot and quantum-well (QW) laser with identical structure, both emitting at 1100 nm.
Abstract: Comparative near-field and beam-quality (M2) measurements on narrow stripe quantum-dot (QD) and quantum-well (QW) lasers of identical structure, both emitting at 1100 nm, are presented. Intrinsic suppression of filamentation in the QD lasers is observed. QD lasers emitting at 1300 nm again show no filamentation. For a 6-μm-stripe, QW laser, M2 increases from 2.6 to 6.1 with output power increasing from 5 to 60 mW and with increasing stripe width (20 mW, 3→10 μm, M2=2.6→4.7). In the QD lasers, filamentation is suppressed up to 8 μm (1100 nm) and 9 μm (1300 nm) stripe width and no dependence on output power is observed.
TL;DR: In this paper, quantum-coherence phenomena in a semiconductor quantum-dot structure were explored and the authors predicted the occurrence of inversionless gain, electromagnetically induced transparency, and refractive index enhancement in the transient regime for dephasing rates typical under room temperature and high excitation conditions.
Abstract: This paper explores quantum-coherence phenomena in a semiconductor quantum-dot structure. The calculations predict the occurrence of inversionless gain, electromagnetically induced transparency, and refractive-index enhancement in the transient regime for dephasing rates typical under room temperature and high excitation conditions. They also indicate deviations from atomic systems because of strong many-body effects. Specifically, Coulomb interaction involving states of the quantum dots and the continuum belonging to the surrounding quantum well leads to collision-induced population redistribution and many-body energy and field renormalizations that modify the magnitude, spectral shape, and time dependence of quantum-coherence effects.
TL;DR: In this paper, a low threshold incident pump power of less than 1 mW was achieved for the second bandedge near the X and M points, with only 15×15 lattice points.
Abstract: Square-lattice bandedge lasers are realized by room-temperature optical pumping of photonic crystal air-bridge slabs of InGaAsP quantum wells emitting at 1.5 μm. Lasing modes corresponding to the second bandedges near the X and M points are identified from their spectral positions and polarization directions. A low threshold incident pump power of less than 1 mW is achieved for the laser operating at the second bandedge near the X and M points, with only 15×15 lattice points. The measured characteristics of the bandedge lasers closely agree with the result of calculations based on the plane-wave-expansion method and the finite-difference time-domain method.
TL;DR: In this paper, an experimental determination of the internal polarization field in GaInN/GaN quantum wells, due to piezoelectric and spontaneous polarization, utilizing the quantum confined Stark effect, was reported.
Abstract: We report an experimental determination of the internal polarization field in GaInN/GaN quantum wells, due to piezoelectric and spontaneous polarization, utilizing the quantum confined Stark effect, with fields as large as 3.1 MV/cm at 22% In. From its dependence on quantum well composition and strain, we find that the total field in GaInN is a linear combination of polarization charges from GaN and InN. The piezoelectric constants d31 for GaN and InN derived from our data are 1.05±0.05 pm/V and 3.7±0.5 pm/V, in fair agreement with theoretical data.
TL;DR: Retardation effects, theoretically predicted more than 35 years ago, are observed in the spectrum of two-dimensional plasmons in high-electron-mobility GaAs/AlGaAs quantum wells.
Abstract: Retardation effects, theoretically predicted more than 35 years ago, are observed in the spectrum of two-dimensional plasmons in high-electron-mobility GaAs/AlGaAs quantum wells. In zero magnetic field, a strong reduction of the resonant plasma frequency is observed due to the hybridization of the plasma and light modes. In a perpendicular magnetic field B, hybrid cyclotron-plasmon modes appear with a very unusual dependence of the frequency on B field. Experimental results are in excellent agreement with the theory.
TL;DR: Injection of spin-polarized hot-electron current from a magnetic tunnel transistor into GaAs is demonstrated by the observation of polarized light emission from a GaAs/In( 0.2)Ga(0.8)As multiple quantum well light-emitting diode.
Abstract: Injection of spin-polarized hot-electron current from a magnetic tunnel transistor into GaAs is demonstrated by the observation of polarized light emission from a GaAs/In(0.2)Ga(0.8)As multiple quantum well light-emitting diode. Electroluminescence from the quantum wells shows a polarization of approximately 10% after subtraction of a linear background polarization. The polarization shows a strong dependence on the bias voltage across the diode, which may originate from changes in the electron spin relaxation rate in the quantum wells under varying bias conditions.
TL;DR: In this article, a transparent AlN base layer was used to achieve sub-300 nm electroluminescence from an AlGaN p-n junction single quantum well light emitting diode.
Abstract: We report the use of a novel transparent AlN base layer to achieve sub-300 nm electroluminescence from an AlGaN p-n junction single quantum well light emitting diode grown on sapphire by metal organic chemical vapor deposition. For unpackaged devices tested on wafer at a continuous current of 120 mA, an optical power of 2.4 µW was achieved. Peak emission was 292 nm, with very little secondary wavelength emission.