Topic
Quantum well
About: Quantum well is a research topic. Over the lifetime, 44627 publications have been published within this topic receiving 674023 citations. The topic is also known as: QW & quantum potential well.
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TL;DR: In this article, Grating-coupled external-cavity quantum-cascade laser amplifiers were studied for temperatures from 80 to 230 K. At 80 K, a tuning range of ∼65-88 nm were obtained for 4.5 and 5.1 μm amplifiers, respectively.
Abstract: Grating-coupled external-cavity quantum-cascade lasers were studied for temperatures from 80 to 230 K. At 80 K, a tuning range of ∼65–88 nm are obtained for 4.5 and 5.1 μm laser amplifiers, respectively. The tuning ranges for both narrowed substantially with increasing temperature, to ∼23 nm at 203 K. The threshold varied slowly versus wavelength, while the efficiency appeared to be close to optimum toward wavelengths shorter than the free running wavelength.
117 citations
TL;DR: In this article, the authors reported a quantum dot-like behavior of GaInNAs due to composition nonuniformity of N and In in GaNAs/GaAs quantum wells.
Abstract: We report a quantum dot-like behavior of GaInNAs due to composition nonuniformity of N and In in GaInNAs/GaAs quantum wells (QWs). Images of cross-sectional transmission electron microscopy show that the wells of both Ga0.7In0.3As/GaAs and Ga0.7In0.3N0.02As0.98/GaAs are undulated due to lateral variations in strain. This effect is more pronounced in the N-containing QWs due to nonuniform In and N concentrations. Rapid thermal annealing causes a blueshift of the photoluminescence (PL) peak, and results in a splitting of the as-grown broad PL emission into two peaks. The In and N composition fluctuation after annealing becomes predominantly bimodal. The low-energy PL peak is attributed to excitons localized at deep levels, which are originated from In- and N-rich regions in the wells acting as quantum dots (QD). The high-energy peak PH is likely due to the excitons of the 2D QWs. To reduce the local strain, N atoms are preferentially localized in the In-rich regions, so the separation between these two peak...
117 citations
TL;DR: In this article, the authors demonstrate highly efficient, low threshold InAs quantum dot lasers epitaxially grown on on on-axis (001) GaP/Si substrates using molecular beam epitaxy.
Abstract: We demonstrate highly efficient, low threshold InAs quantum dot lasers epitaxially grown on on-axis (001) GaP/Si substrates using molecular beam epitaxy Electron channeling contrast imaging measurements show a threading dislocation density of 73 × 106 cm−2 from an optimized GaAs template grown on GaP/Si The high-quality GaAs templates enable as-cleaved quantum dot lasers to achieve a room-temperature continuous-wave (CW) threshold current of 95 mA, a threshold current density as low as 132 A/cm2, a single-side output power of 175 mW, and a wall-plug-efficiency of 384% at room temperature As-cleaved QD lasers show ground-state CW lasing up to 80 °C The application of a 95% high-reflectivity coating on one laser facet results in a CW threshold current of 67 mA, which is a record-low value for any kind of Fabry-Perot laser grown on Si
117 citations
TL;DR: In this article, the polarization effects in GaN/AlGaN multiple quantum wells (MQWs) with different c-axis orientation by means of excitation-dependent photoluminescence (PL) analysis were studied.
Abstract: Polarization effects have been studied in GaN/AlGaN multiple quantum wells (MQWs) with different c-axis orientation by means of excitation-dependent photoluminescence (PL) analysis Quantum structures were grown on [0001]-oriented sapphire substrates (C plane) and single-crystalline [1100]-oriented freestanding GaN (M plane) using the metalorganic chemical vapor deposition technique Strong PL spectrum line blueshifts (up to 140 meV) which are correlated with the excitation intensity have been obtained for C-plane MQWs, whereas no shift has been observed for M-plane MQWs Theoretical calculations and comparison with the PL data confirm that the built-in electric field for C-plane structures is much stronger than the field present for M-plane MQWs In the former case, the excitation-induced blueshift of the PL line is due to the screening of the built-in electric field by photoinjected carriers, which is consistent with the field strength of 123 MV/cm in the absence of excitation
117 citations
TL;DR: In this article, the mismatch strain of molecular beam epitaxy (MBE) deposited InGaAs on GaAs to induce a transition from the two-dimensional growth mode to the three-dimensional (Stranski-Krastanow) growth mode is presented.
Abstract: A one step method for the production of quantum dots is presented. The method exploits the mismatch strain of molecular beam epitaxy (MBE) deposited InGaAs on GaAs to induce a transition from the two‐dimensional growth mode to the three‐dimensional (Stranski–Krastanow) growth mode. The cluster size is limited to quantum dimensions by precisely controlling the amount of InGaAs that is deposited in order to cause the growth mode transition. Very narrow lateral size distributions with standard deviations of 14% on the dot area have been obtained. Smooth MBE growth of GaAs over these clusters produces a layer of quantum dots, whose high quality and uniformity has been observed with transmission electron microscopy, atomic force microscopy, and photoluminescence (PL). The quantum dot PL intensity is enhanced compared to a reference quantum well. Resonances in photoluminescence excitation (PLE) spectra suggest that the density of states in these dots has minima close to zero between the quantum states, as expec...
117 citations