共查询到14条相似文献,搜索用时 62 毫秒
1.
We investigate the molecular beam epitaxy growth of metamorphic InxGal-xAs materials (x up to 0.5) on GaAs substrates systematically. Optimization of structure design and growth parameters is aimed at obtaining smooth surface and high optical qualdty. The optimized structures have an average surface roughness of 0.9-1.8 nm. It is also proven by PL measurements that the optical properties of high indium content (55%) InGaAs quantum wells are improved apparently by defect reduction technique and by introducing Sb as a surfactant. These provide us new ways for growing device quality metamorphic structures on GaAs substrates with long-wavelength emissions. 相似文献
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Using a linear graded Inx Ga1-xAs as the buffer layer, positive-intrinsic-negative wavelength-extended In0.6 Ga0.4As photodetectors with 50% cut-off wavelength of 1.9μm at room temperature were grown by using gas-source molecular beam epitaxy, and their performance over a wide temperature range has been extensively investigated. The detectors show typical dark current at bias voltage 50mV and the resistance-area product R0A of 7nA/765Ωcm^2 and 31pA/404kΩcm^2 at 290K and 210K, respectively. The thermal activation energy of the dark current in the temperature range 250-350K is 0.488 eV. 相似文献
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High Characteristic Temperature 1.3μm InAs/GaAs Quantum-Dot Lasers Grown by Molecular Beam Epitaxy 下载免费PDF全文
We report the molecular beam epitaxy growth of 1.3 μm InAs/GaAs quantum-dot (QD) lasers with high characteristic temperature T0. The active region of the lasers consists of five-layer InAs QDs with p-type modulation doping. Devices with a stripe width of 4 μm and a cavity length of 1200 μm are fabricated and tested in the pulsed regime under different temperatures. It is found that T0 of the QD lasers is as high as 532 K in the temperature range from 10°C to 60°C. In addition, the aging test for the lasers under continuous wave operation at 100°C for 72 h shows almost no degradation, indicating the high crystal quality of the devices. 相似文献
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Molecular Beam Epitaxy Growth and Photoluminescence of Type-Ⅱ (GaAs1-xSbx/InyGa1-yAs)/GaAs Bilayer Quantum Well 下载免费PDF全文
We report a systematical study on the molecular beam epitaxy growth and optical property of (GaAs1-xSbx/InyGa1-yAs)/GaAs bilayer quantum we]] (BQW) structures. It is shown that the growth temperature of the wells and the sequence of layer growth have significant influence on the interface quality and the subsequent photoluminescence (PL) spectra. Under optimized growth conditions, three high-quality (GaAsSb0.29/In0.4 GaAs)/GaAs BQWs are successfully fabricated and a room temperature PL at 1314 nm is observed. The transition mechanism in the BQW is also discussed by photoluminescence and photoreflectance measurements. The results confirm experimentally a type-Ⅱ band alignment of the interface between the GaAsSb and InGaAs layers. 相似文献
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Influence of Growth Parameters of Frequency-Radio Plasma Nitrogen Source on Extending Emission Wavelengths from 1.31 μm to 1.55 μm GaInNAs/GaAs Quantum Wells Grown by Molecular-Beam Epitaxy 下载免费PDF全文
High (42.5%) indium content GaInNAs/GaAs quantum wells with room temperature emission wavelength from 1.3μm to 1.5μm range were successfully grown by Radio Frequency Plasma Nitrogen source assisted Molecular Beam Epitaxy, The growth parameters of plasma power and N2 flow rate were optimized systematically to improve the material quality. Photoluminescence and transmission electron microscopy measurements showed that the optical and crystal quality of the 1.54μm GaInNAs/GaAs QWs was kept as comparable as that in 1.31 μm. 相似文献
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Top-illuminated metamorphic InGaAs p-i-n photodetectors (PDs) with 50% cut-off wavelength of 1.75 μm at room temperature are fabricated on GaAs substrates. The PDs are grown by a solid-source molecular beam epitaxy system. The large lattice mismatch strain is accommodated by growth of a linearly graded buffer layer to create a high quality virtual InP substrate indium content in the metamorphic buffer layer linearly changes from 2% to 60%. The dark current densities are typically 5 × 10^-6 A/cm^2 at 0 V bias and 2.24 × 10^-4 A/cm^2 at a reverse bias of 5 V. At a wavelength of 1.55 μm, the PDs have an optical responsivity of 0.48 A/W, a linear photoresponse up to 5 mW optical power at -4 V bias. The measured -3 dB bandwidth of a 32 μm diameter device is 7 GHz. This work proves that InGaAs buffer layers grown by solid source MBE are promising candidates for GaAs-based long wavelength devices. 相似文献
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The structural and optical characteristics of InP-based compressively strained InGaAs quantum wells have been significantly improved by using gas source molecular beam epitaxy grown InAs/Ino.53Ga0.47As digital alloy triangular well layers and tensile Ino.53Ga0.47As/InAiGaAs digital alloy barrier layers. The x-ray diffraction and transmission electron microscope characterisations indicate that the digital alloy structures present favourable lattice quality. Photo- luminescence (PL) and electroluminescence (EL) measurements show that the use of digital alloy barriers offers better optical characteristics than that of conventional random alloy barriers. A significantly improved PL signal of around 2.1μm at 300 K and an EL signal of around 1.95μm at 100 K have been obtained. 相似文献
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Structure,Electrical,and Optical Properties of Nb-doped BaTiO3 Thin Films Grown by Laser Molecular Beam Epitaxy 下载免费PDF全文
Structure,electrical,and optical properties of Nb-doped BaTiO3 (Nb:BTO) thin films on MgO substrates grownby laser molecular beam epitaxy with increasing Nb content were investigated.The Nb:BTO thin films with high crystallinity are epitaxially grown on MgO substrates.With more Nb-doped content,the impurity phases are found in Nb:BTO thin films.Hall measurement at room temperature confirms that the charge carriers of the Nb:BTO thin films are n-type.When the Nb-doped content increases,the carrier concentration and carrier mobility increase.Meanwhile the optical transmittance decreases with the increase of the Nb-doping,and the width of the forbidden band in each group is not affected by the presence of Nb in the samples.Raman spectra show that the structural phase transition may occur with the increase of the Nb-doping content,in the meantime more defects and impurities exist in the Nb:BTO thin films. 相似文献
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Properties of InGaP/GaAs Grown by Solid-Source Molecular Beam Epitaxy with a GaP Decomposition Source 下载免费PDF全文
Lattice-matched InGaP on GaAs (001) was successfully grown by solid-source molecular beam epitaxy witha GaP decomposition source. A 0.5-μm-thick InGaP epilayer shows photoluminescence peak energy as large as 1.991eV at 15K, the full width at half maximum as small as 9.4meV and x-ray diffraction rocking curve linewidth as narrow as 25 arcsec. The electron mobilities of undoped and Si-doped InGaP layers obtained by Hall measurements are comparable to similar InGaP/GaAs heterojunction grown by solid-source molecular beamepitaxy with other sources or other growth techniques. The results reveal that the InGaP/GaAs heterojunction grown bY the present growth way have great potential applications for semiconductor devices. 相似文献
10.
By optimizing the molecule beam epitaxy growth condition, the quality of quantum cascade (QC) material has greatly been improved. The spectrum of double x-ray diffraction indicates that the interface between the constituent layers is very smooth, the lattice mismatch between the epilayer and the substrate is less than 0.1%,and the periodicity fluctuation of the active region is not more than 4.2%. The QC laser with the emission wavelength of about 5.1μm is operated at the threshold of 0.73 kA/cm^2 at liquid nitrogen temperature with the repetition rate of lOkHz and at a duty cycle of 1%. Meanwhile, the performance of the laser can be improved with suitable post process techniques such as the metallic ohmic contact technology. 相似文献
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Incorporation Behaviour of Arsenic and Phosphorus in GaAsP/GaAs Grown by Solid Source Molecular Beam Epitaxy with a GaP Decomposition Source 下载免费PDF全文
The incorporation behaviour of arsenic and phosphorus in the GaAsP ternary alloy under phosphorus-rich conditions is studied based on the incorporation coefficient model and the growth diffusion model combined with the alloy composition data obtained by high resolution x-ray diffraction analysis. It is found that As adatoms have longer surface lifetime and longer migration length than those of P adatoms, which leads to an arsenic incorporation efficiency much higher than that of phosphorous. With the increase of arsenic flux, the surface lifetime of arsenic adatoms decreases due to the competition of As adatoms. The detailed analysis and discussion are given here. 相似文献
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We demonstrate 10 Gb/s directly-modulated 1.3 μm InAs quantum-dot (QD) lasers grown on GaAs substrates by molecular beam epitaxy. The active region of the QD lasers consists of five-stacked InAs QD layers. Ridge-waveguide lasers with a ridge width of 4 μm and a cavity length of 600 μm are fabricated with standard lithography and wet etching techniques. It is found that the lasers emit at 1293 nm with a very low threshold current of 5 mA at room temperature. Furthermore, clear eye-opening patterns under 10 Gb/s modulation rate at temperatures of up to 50oC are achieved by the QD lasers. The results presented here have important implications for realizing low-cost, low-power-consumption, and high-speed light sources for next-generation communication systems. 相似文献
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