Showing papers on "Quantum well published in 2008"
TL;DR: This work reports the first multi-quantum-well (MQW) core/shell nanowire heterostructures based on well-defined III-nitride materials that enable lasing over a broad range of wavelengths at room temperature and demonstrates a new level of complexity in nanowires, which potentially can yield free-standing injection nanolasers.
Abstract: Rational design and synthesis of nanowires with increasingly complex structures can yield enhanced and/or novel electronic and photonic functions. For example, Ge/Si core/shell nanowires have exhibited substantially higher performance as field-effect transistors and low-temperature quantum devices compared with homogeneous materials, and nano-roughened Si nanowires were recently shown to have an unusually high thermoelectric figure of merit. Here, we report the first multi-quantum-well (MQW) core/shell nanowire heterostructures based on well-defined III-nitride materials that enable lasing over a broad range of wavelengths at room temperature. Transmission electron microscopy studies show that the triangular GaN nanowire cores enable epitaxial and dislocation-free growth of highly uniform (InGaN/GaN)n quantum wells with n=3, 13 and 26 and InGaN well thicknesses of 1-3 nm. Optical excitation of individual MQW nanowire structures yielded lasing with InGaN quantum-well composition-dependent emission from 365 to 494 nm, and threshold dependent on quantum well number, n. Our work demonstrates a new level of complexity in nanowire structures, which potentially can yield free-standing injection nanolasers.
713 citations
TL;DR: Remarkably, the topological quantum phase transition between the conventional insulating state and the quantum spin Hall state can be continuously tuned by the gate voltage, enabling quantitative investigation of this novel phase transition.
Abstract: The quantum spin Hall (QSH) state is a topologically nontrivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel effect has been predicted and observed in HgTe quantum wells and in this Letter we predict a similar effect arising in Type-II semiconductor quantum wells made from InAs/GaSb/AlSb. The quantum well exhibits an "inverted" phase similar to HgTe/CdTe quantum wells, which is a QSH state when the Fermi level lies inside the gap. Due to the asymmetric structure of this quantum well, the effects of inversion symmetry breaking are essential. Remarkably, the topological quantum phase transition between the conventional insulating state and the quantum spin Hall state can be continuously tuned by the gate voltage, enabling quantitative investigation of this novel phase transition.
616 citations
TL;DR: In this paper, the authors present an analytical solution of the helical edge states and explicitly demonstrate their topological stability in HgTe/(Hg,Cd)Te QWs.
Abstract: The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Recently, a new class of topological insulators has been proposed. These topological insulators have an insulating gap in the bulk, but have topologically protected edge states due to the time reversal symmetry. In two dimensions the helical edge states give rise to the quantum spin Hall (QSH) effect, in the absence of any external magnetic field. Here we review a recent theory which predicts that the QSH state can be realized in HgTe/CdTe semiconductor quantum wells (QWs). By varying the thickness of the QW, the band structure changes from a normal to an “inverted” type at a critical thickness d c . We present an analytical solution of the helical edge states and explicitly demonstrate their topological stability. We also review the recent experimental observation of the QSH state in HgTe/(Hg,Cd)Te QWs. We review both the fabrication of the sample and the experimental setup. For thin QWs w...
603 citations
TL;DR: This work predicts that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{1-y}Mn{y}Te quantum wells, without an external magnetic field and the associated Landau levels.
Abstract: The quantum Hall effect is usually observed when a two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{1-y}Mn{y}Te quantum wells, without an external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.
488 citations
TL;DR: The use of quaternary alloys enables an independent control over interface polarization charges and bandgap and has been suggested as a method to reduce electron leakage from the active region, a carrier loss mechanism that can reduce efficiency at high injection currents as mentioned in this paper.
Abstract: Blue multi-quantum-well light-emitting diodes (LEDs) with GaInN quantum wells and polarization-matched AlGaInN barriers are grown by metal-organic chemical vapor deposition. The use of quaternary alloys enables an independent control over interface polarization charges and bandgap and has been suggested as a method to reduce electron leakage from the active region, a carrier loss mechanism that can reduce efficiency at high injection currents—an effect known as the efficiency droop. The GaInN∕AlGaInN LEDs show reduced forward voltage, reduced efficiency droop, and improved light-output power at large currents compared to conventional GaInN∕GaN LEDs.
478 citations
TL;DR: In this paper, the authors present an analytical solution of the helical edge states and explicitly demonstrate their topological stability in HgTe/(Hg,Cd)Te quantum wells.
Abstract: The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Recently, a new class of topological insulators has been proposed. These topological insulators have an insulating gap in the bulk, but have topologically protected edge states due to the time reversal symmetry. In two dimensions the helical edge states give rise to the quantum spin Hall (QSH) effect, in the absence of any external magnetic field. Here we review a recent theory which predicts that the QSH state can be realized in HgTe/CdTe semiconductor quantum wells. By varying the thickness of the quantum well, the band structure changes from a normal to an "inverted" type at a critical thickness $d_c$. We present an analytical solution of the helical edge states and explicitly demonstrate their topological stability. We also review the recent experimental observation of the QSH state in HgTe/(Hg,Cd)Te quantum wells. We review both the fabrication of the sample and the experimental setup. For thin quantum wells with well width $d_{QW} 6.3$ nm), the nominally insulating regime shows a plateau of residual conductance close to $2e^2/h$. The residual conductance is independent of the sample width, indicating that it is caused by edge states. Furthermore, the residual conductance is destroyed by a small external magnetic field. The quantum phase transition at the critical thickness, $d_c= 6.3$ nm, is also independently determined from the occurrence of a magnetic field induced insulator to metal transition.
420 citations
TL;DR: In this paper, the carrier distribution in multi quantum well (multi-QW) InGaN light-emitting diodes was studied and it was shown that, no matter how many QWs are grown, only the QW nearest the p layer emits light under electrical pumping, which can limit the performances of high power devices.
Abstract: We study the carrier distribution in multi quantum well (multi-QW) InGaN light-emitting diodes. Conventional wisdom would assume that a large number of QWs lead to a smaller carrier density per QW, enabling efficient carrier recombination at high currents. We use angle-resolved far-field measurements to determine the location of spontaneous emission in a series of multi-QW samples. They reveal that, no matter how many QWs are grown, only the QW nearest the p layer emits light under electrical pumping, which can limit the performances of high-power devices.
326 citations
TL;DR: In this paper, low-energy electron microscopy (LEEM) was used to measure the reflectivity of low energy electrons from graphitized graphitized silicon carbide (SiC) substrate.
Abstract: Low-energy electron microscopy (LEEM) was used to measure the reflectivity of low-energy electrons from graphitized $\mathrm{SiC}(0001)$. The reflectivity shows distinct quantized oscillations as a function of the electron energy and graphite thickness. Conduction bands in thin graphite films form discrete energy levels whose wave vectors are normal to the surface. Resonance of the incident electrons with these quantized conduction band states enhances electrons to transmit through the film into the $\mathrm{SiC}$ substrate, resulting in dips in the reflectivity. The dip positions are well explained using tight-binding and first-principles calculations. The graphite thickness distribution can be determined microscopically from LEEM reflectivity measurements.
324 citations
TL;DR: The ability to change the degree of hybridization of a donor electron state between the coulombic potential of its donor atom and that of a nearby quantum well in a silicon transistor has now been achieved as mentioned in this paper.
Abstract: The ability to change the degree of hybridization of a donor electron state between the coulombic potential of its donor atom and that of a nearby quantum well in a silicon transistor has now been achieved. This is a promising step in the development of atomic-scale quantum control.
323 citations
TL;DR: In this article, the authors used pulsed electroluminescence measurements to determine the genesis of efficiency droop observed at injection levels of approximately ⩾50A∕cm2.
Abstract: Multiple quantum well (MQW) InGaN light emitting diodes with and without electron blocking layers, with relatively small and large barriers, with and without p-type doping in the MQW region emitting at ∼420nm were used to determine the genesis of efficiency droop observed at injection levels of approximately ⩾50A∕cm2. Pulsed electroluminescence measurements, to avoid heating effects, revealed that the efficiency peak occurs at ∼900A∕cm2 current density for the Mg-doped barrier, near 550A∕cm2 for the lightly doped n-GaN injection layer, meant to bring the electron injection level closer to that of holes, and below 220A∕cm2 for the undoped InGaN barrier cases. For samples with GaN barriers (larger band discontinuity) or without p-AlGaN electron blocking layers the droop occurred at much lower current densities (⩽110A∕cm2). In contrast, photoluminescence measurements revealed no efficiency droop for optical carrier generation rates corresponding to the maximum current density employed in pulsed injection mea...
319 citations
TL;DR: In this paper, an electrically pumped ZnO quantum well diode laser was used to emit lasing at room temperature with a very low threshold injection current density of 10 εA/cm2.
Abstract: Electrically pumped ZnO quantum well diode lasers are reported. Sb-doped p-type ZnO/Ga-doped n-type ZnO with an MgZnO/ZnO/MgZnO quantum well embedded in the junction was grown on Si by molecular beam epitaxy. The diodes emit lasing at room temperature with a very low threshold injection current density of 10 A/cm2. The lasing mechanism is exciton-related recombination and the feedback is provided by close-loop scattering from closely packed nanocolumnar ZnO grains formed on Si.
TL;DR: In this article, room temperature polariton lasing at λ∼345nm in a hybrid AlInN∕AlGaN multiple quantum well microcavity (MQW-MC) was reported.
Abstract: The authors report room temperature polariton lasing at λ∼345nm in a hybrid AlInN∕AlGaN multiple quantum well microcavity (MQW-MC) containing a GaN∕AlGaN MQW active region, i.e., the achievement under nonresonant optical excitation of coherent light emission of a macroscopic population of polaritons occupying the lowest energy state of the lower polariton branch. This was made possible by taking advantage of the efficient relaxation of polaritons in a MQW-MC exhibiting a large vacuum Rabi splitting ΩVRS=56meV.
TL;DR: Experimental realization of an electrically pumped semiconductor polariton light-emitting device, which emits directly from polariton states at a temperature of 235 K, represents a substantial step towards the realization of ultra-efficient polaritonic devices with unprecedented characteristics.
Abstract: The increasing ability to control light-matter interactions at the nanometre scale has improved the performance of semiconductor lasers in the past decade. The ultimate optimization is realized in semiconductor microcavities, in which strong coupling between quantum-well excitons and cavity photons gives rise to hybrid half-light/half-matter polariton quasiparticles. The unique properties of polaritons-such as stimulated scattering, parametric amplification, lasing, condensation and superfluidity-are believed to provide the basis for a new generation of polariton emitters and semiconductor lasers. Until now, polariton lasing and nonlinearities have only been demonstrated in optical experiments, which have shown the potential to reduce lasing thresholds by two orders of magnitude compared to conventional semiconductor lasers. Here we report an experimental realization of an electrically pumped semiconductor polariton light-emitting device, which emits directly from polariton states at a temperature of 235 K. Polariton electroluminescence data reveal characteristic anticrossing between exciton and cavity modes, a clear signature of the strong coupling regime. These findings represent a substantial step towards the realization of ultra-efficient polaritonic devices with unprecedented characteristics.
TL;DR: The improvement in the maximum operating temperature is achieved by using a three-quantum-well active region design with resonant-phonon depopulation and by utilizing copper, instead of gold, for the cladding material in the metal-metal waveguides.
Abstract: We report terahertz quantum cascade lasers operating in pulsed mode at an emission frequency of 3 THz and up to a maximum temperature of 178 K. The improvement in the maximum operating temperature is achieved by using a three-quantum-well active region design with resonant-phonon depopulation and by utilizing copper, instead of gold, for the cladding material in the metal-metal waveguides.
TL;DR: In this article, the effect of growth and design parameters on the performance of Si-doped GaN/AlN multiquantum-well (MQW) structures for inter-band optoelectronics in the near infrared was studied.
Abstract: We have studied the effect of growth and design parameters on the performance of Si-doped GaN/AlN multiquantum-well (MQW) structures for intersubband optoelectronics in the near infrared. The samples under study display infrared absorption in the 1.3–1.9 μm wavelength range, originating from the photoexcitation of electrons from the first to the second electronic level in the QWs. A commonly observed feature is the presence of multiple peaks in both intersubband absorption and interband emission spectra, which are attributed to monolayer thickness fluctuations in the quantum wells. These thickness fluctuations are induced by dislocations and eventually by cracks or metal accumulation during growth. The best optical performance is attained in samples synthesized with a moderate Ga excess during the growth of both the GaN QWs and the AlN barriers without growth interruptions. The optical properties are degraded at high growth temperatures (>720 °C) due to the thermal activation of the AlN etching of GaN. Fr...
TL;DR: In this article, a coherent coupling between surface plasmon polaritons (SPP) and quantum well excitons in a hybrid metal-semiconductor nanostructure is reported.
Abstract: We report measurements of a coherent coupling between surface plasmon polaritons (SPP) and quantum well excitons in a hybrid metal-semiconductor nanostructure. The hybrid structure is designed to optimize the radiative exciton-SPP interaction which is probed by low-temperature, angle-resolved, far-field reflectivity spectroscopy. As a result of the coupling, a significant shift of $\ensuremath{\sim}7\text{ }\text{ }\mathrm{meV}$ and an increase in broadening by $\ensuremath{\sim}4\text{ }\text{ }\mathrm{meV}$ of the quantum well exciton resonance are observed. The experiments are corroborated by a phenomenological coupled-oscillator model predicting coupling strengths as large as 50 meV in structures with optimized detunings between the coupled exciton and SPP resonances. Such a strong interaction can, e.g., be used to enhance the luminescence yield of semiconductor quantum structures or to amplify SPP waves.
TL;DR: In this article, a GaN-based vertical-cavity surface-emitting laser (VCSEL) was demonstrated to operate at room temperature in an InGaN/GaN quantum well active layer.
Abstract: We report the demonstration of CW lasing at room temperature in a GaN-based vertical-cavity surface-emitting laser (VCSEL) by current injection. The active region of the VCSEL consisted of a two-pair InGaN/GaN quantum well active layer. The optical cavity consisted of a 7-λ-thick GaN semiconductor layer and an indium tin oxide layer for p-contact embedded between two SiO2/Nb2O5 dielectric distributed Bragg reflectors. The VCSEL was mounted on a Si substrate by wafer bonding and the sapphire substrate was removed by laser lift-off. Under CW operation for an 8-µm aperture device, the threshold current was 7.0 mA and the emission wavelength was approximately 414 nm.
TL;DR: By using strong optical injection locking, resonance frequency enhancement in excess of 100 GHz in semiconductor lasers is reported, showing the broad applicability of the technique and that the coupling Q is the figure-of-merit for Resonance frequency enhancement.
Abstract: By using strong optical injection locking, we report resonance frequency enhancement in excess of 100 GHz in semiconductor lasers. We demonstrate this enhancement in both distributed feedback (DFB) lasers and vertical-cavity surface-emitting lasers (VCSELs), showing the broad applicability of the technique and that the coupling Q is the figure-of-merit for resonance frequency enhancement. We have also identified the key factors that cause low-frequency roll-off in injection-locked lasers. By increasing the slave laser's DC current bias, we have achieved a record intrinsic 3-dB bandwidth of 80 GHz in VCSELs.
TL;DR: In this paper, the authors studied the low-intensity light pulse propagation through an asymmetric double quantum well via Fano-type interference based on intersubband transitions and showed the generation of ultraslow bright and dark optical solitons in this system.
Abstract: We study the low-intensity light pulse propagation through an asymmetric double quantum well via Fano-type interference based on intersubband transitions. The propagation of the pulse across the quantum well is studied analytically and numerically with the coupled Maxwell-Schr\"odinger equations. We show the generation of ultraslow bright and dark optical solitons in this system. Whether the solitons are dark and bright can be controlled by the ratio of dipole moments of the intersubband transitions. Such investigation of ultraslow optical solitons in the present work may lead to important applications such as high-fidelity optical delay lines and optical buffers in semiconductor quantum wells structure.
TL;DR: In this article, the existence of the helical edge states in HgTe quantum wells and calculate their physical properties are shown. But the results are limited to three dimensions and the surface states are described by single component massless relativistic Dirac fermions in $2+1$ dimensions.
Abstract: The quantum spin Hall (QSH) effect is the property of a new state of matter which preserves time reversal, has an energy gap in the bulk, but has topologically robust gapless states at the edge. Recently, the QSH state has been theoretically predicted and experimentally observed in HgTe quantum wells [B. A. Bernevig et al., Science 34, 1757 (2006); M. Konig et al., ibid. 318, 766 (2007)]. In this work, we start from realistic tight-binding models and demonstrate the existence of the helical edge states in HgTe quantum wells and calculate their physical properties. We also show that three-dimensional HgTe is a topological insulator under uniaxial strain and show that the surface states are described by single-component massless relativistic Dirac fermions in $2+1$ dimensions. Experimental predictions are made based on the quantitative results obtained from realistic calculations.
TL;DR: The chiral stationary phase for high-performance liquid chromatography showed good chiral recognition ability towards various racemates, including Na6(CO3)(SO4)2, Na2SO4, and Na2CO3.
Abstract: Keywords: molecular beam epitaxy ; nanowires ; photoluminescence ; quantum wells ; Cleaved Edge Overgrowth ; Core-Shell ; Growth ; Electron ; Silicon ; Mechanism ; Diffusion ; Wires ; Au Reference EPFL-ARTICLE-148571doi:10.1002/smll.200701091 Record created on 2010-04-28, modified on 2017-05-10
TL;DR: A novel high-quality (Q) factor optical resonator using a subwavelength high-contrast grating with in-plane resonance and surface-normal emission with a Q factor of >14,000 is reported.
Abstract: We report a novel high-quality (Q) factor optical resonator using a subwavelength high-contrast grating (HCG) with in-plane resonance and surface-normal emission. We show that the in-plane resonance is manifested is by a sharp, asymmetric lineshape in the surface-normal reflectivity spectrum. The simulated Q factor of the resonator is shown to be as high as 500,000. A HCG-resonator was fabricated with an InGaAs quantum well active region sandwiched in-between AlGaAs layers and a Q factor of >14,000 was inferred from the photoluminescence linewidth of 0.07 nm, which is currently limited by instrumentation. The novel HCG resonator design will serve as a potential platform for many devices including surface emitting lasers, optical filters, and biological or chemical sensors.
TL;DR: In this paper, the authors demonstrate quantum cascade laser at an emitting wavelength of 4.6μm, which are capable of room temperature, high power continuous wave (cw) operation.
Abstract: We demonstrate quantum cascade lasers at an emitting wavelength of 4.6μm, which are capable of room temperature, high power continuous wave (cw) operation. Buried ridge geometry with a width of 9.8μm was utilized. A device with a 3mm cavity length that was epilayer-down bonded on a diamond submount exhibited a maximum output power of 1.3W at room temperature in cw operation. The maximum output power at 80K was measured to be 4W, with a wall plug efficiency of 27%.
Patent•
27 Nov 2008
TL;DR: In this article, the authors proposed a quantum well-structured active layer to suppress an increase of a piezoelectric field caused by lattice mismatch between barrier layers and a well layer.
Abstract: PROBLEM TO BE SOLVED: To provide a nitride semiconductor device capable of suppressing an increase of a piezoelectric field caused by lattice mismatch between barrier layers and a well layer. SOLUTION: The nitride semiconductor device has an active layer 3 having a quantum well structure. The active layer 3 has first/second barrier layers 311, 312 composed of Al a In b Ga 1-a-b N (0 x In y Ga 1-x-y N (0 COPYRIGHT: (C)2009,JPO&INPIT
TL;DR: In this article, a novel gain media based on staggered InGaN quantum wells (QWs) grown by metal-organic chemical vapor deposition was demonstrated as improved active region for visible light emitters.
Abstract: A novel gain media based on staggered InGaN quantum wells (QWs) grown by metal-organic chemical vapor deposition was demonstrated as improved active region for visible light emitters. Fermi's golden rule indicates that InGaN QW with step-function like In content in the well leads to significantly improved radiative recombination rate and optical gain due to increased electron-hole wavefunction overlap, in comparison to that of conventional InGaN QW. Spontaneous emission spectra of both conventional and staggered InGaN QW were calculated based on energy dispersion and transition matrix element obtained by 6-band k middotp formalism for wurtzite semiconductor, taking into account valence-band-states mixing, strain effects, and polarization-induced electric fields. The calculated spectra for the staggered InGaN QW showed enhancement of radiative recombination rate, which is in good agreement with photoluminescence and cathodoluminescence measurements at emission wavelength regime of 425 and 500 nm. Experimental results of light-emitting diode (LED) structures utilizing staggered InGaN QW also show significant improvement in output power. Staggered InGaN QW allows polarization engineering leading to improved luminescence intensity and LED output power as a result of enhanced radiative recombination rate.
TL;DR: In this article, the Hartree-Fock and Heitler-London approaches are improved by a full two-exciton calculation which includes the van der Waals effect.
Abstract: The exciton-exciton interaction is investigated for quasi-two-dimensional quantum structures. A bosonization scheme is applied including the full spin structure. For generating the effective interaction potentials, the Hartree-Fock and Heitler-London approaches are improved by a full two-exciton calculation which includes the van der Waals effect. With these potentials the biexciton formation in bilayer systems is investigated. For coupled quantum wells the two-body scattering matrix is calculated and employed to give a modified relation between exciton density and blue shift. Such a relation is of central importance for gauging exciton densities in experiments which pave the way toward Bose-Einstein condensation of excitons.
TL;DR: In this paper, the electronic and absorption properties of the intermediate band (IB) formed by a three dimensional structure of InAs/GaAs quantum dots (QDs) arranged in a periodic array are analyzed.
Abstract: We present a theoretical study of the electronic and absorption properties of the intermediate band (IB) formed by a three dimensional structure of InAs/GaAs quantum dots (QDs) arranged in a periodic array. Analysis of the electronic and absorption structures suggests that the most promising design for an IB solar cell material, which will exhibit its own quasi-Fermi level, is to employ small QDs (~6–12 nm QD lateral size). The use of larger QDs leads to extension of the absorption spectra into a longer wavelength region but does not provide a separate IB in the forbidden energy gap.
TL;DR: In this article, hole distribution in InGaN∕GaN multiple quantum well (MQW) visible light-emitting diodes (LEDs) was investigated using conventional blue LEDs and dual-wavelength blue-green LEDs.
Abstract: Carrier distributions governed by hole transport in InGaN∕GaN multiple quantum well (MQW) visible light-emitting diodes (LEDs) were investigated using conventional blue LEDs and dual-wavelength blue-green LEDs. It was found that holes were dominantly distributed in the QW close to the p-GaN layer in LEDs with conventional MQW active regions at a current of 20mA. A decrease in the thickness or the height of the quantum-well potential barrier enhanced hole injection into the MQWs located near the n-GaN layer. Reducing the thickness of a GaN quantum-well barrier between the blue QW and green QW did not degrade the electroluminescence (EL) intensity of the LED. In contrast, reducing the potential height of the barrier with material of possibly compromised quality resulted in a degradation of the EL intensity of the LED.
TL;DR: In this article, the optical characteristics of InGaN-based multiple quantum well-light-emitting diodes (LEDs) with peak emission ranging from green to ultraviolet (UV) over a wide injection range were compared.
Abstract: We present a comparative study on the optical characteristics of InGaN-based multiple quantum well light-emitting diodes (LEDs) with peak emission ranging from green to ultraviolet (UV) over a wide injection range. It is found that by pulsing the LEDs with a duty cycle that is below 1%, thermally induced peak red shift and efficiency reduction are largely eliminated. The current dependence of both the quantum efficiency and peak shift appears to be a strong function of the indium content in the active region. The quantum efficiencies of the blue and green LEDs peak at very low currents and dramatically decrease at high currents, whereas the UV LED has a nearly constant quantum efficiency under high injection conditions. In contrast to the minimal current- induced energy shift in the UV LED, a monotonic blue shift of the peak energy, which has a total amount of ~110 meV-1 kA/cm2, is seen for the green LED. These results offer a strong support for the argument that the current overflow from localized states is the major nonthermal mechanism underlying the efficiency rolloff in InGaN-based visible LEDs.
04 May 2008
TL;DR: In this paper, the realization and modelling of microdisk lasers displaying vertical emission is described, which are THz quantum cascade lasers with metallic gratings fabricated along the circumference of the circumference.
Abstract: We report the realization and modelling of microdisk lasers displaying vertical emission. The devices are THz quantum cascade lasers with metallic gratings fabricated along the circumference.