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Structural and Photoluminescence Properties for Highly Strain-Compensated InGaAs/InA1As Superlattice *
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The effects of strain compensation are investigated by using twenty periods of highly strain-compensated InGaAs/InA1As superlattice. The lattice mismatches of individual layers are as high as about 1%, and the thicknesses are close to critical thicknesses. X-ray diffraction measurements show that lattice imperfectness is not serious but still present, though the structural parameters are within the range of theoretical design criteria for structural stability. Rough interfaces and composition fluctuations are the primary causes for lattice imperfecthess. Photoluminescence measurements show the large thermally activated nonradiative recombination in the sample. In addition, the recombination process gradually evolves from exeitonic recombination at lower temperatures to band-to-band recombination at higher temperatures, which should be considered in device applications. 相似文献
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采用气态源分子束外延方法生长了三种不同结构的扩展波长(室温下50%截止波长为2.4μm) In_xGa_(1-x)As光电探测器材料,并制成了台面型器件.材料的表面形貌、X射线衍射摇摆曲线及光致发光谱表明,在InAlAs/InGaAs异质界面处生长数字梯度超晶格可以明显提高材料质量;器件在室温下的暗电流结果显示,直径为300μm的器件在反向偏压为10mV时,没有生长超晶格结构的器件暗电流为0.521μA,而生长超晶格结构的器件暗电流降到0.480μA.同时,在生长In_xAl_(1-x)As组分线性渐变缓冲层之前首先生长一层InP缓冲层也有利于改善材料质量和器件性能. 相似文献
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Gas Source MBE-Grown Metamorphic InGaAs Photodetectors using InAlAsBuffer and Cap Layers with Cut-off Wavelength up to 2.7
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We report on InP-based metamorphic InGaAs photodiodes grown by gas source molecular beam epitaxy (MBE), in which a relatively thin compositional graded wide band-gap InxAl1-xAs buffer layer is adopted. In the photodiodes, InAiAs is also taken as cap layers, so this structure is suitable for both front and back illuminations. At room temperature the photodiodes show 50% cut-off wavelength of 2.66μm, with measured peak detectivity of 4.91×10^9 cmHz^1/2/W at 2.57μm, and the typical dark current and RoA are 7.68μA/0.94Ωcm^2 and 291 nA/24.29Ωcm^2 at 290 K and 150 K respectively for the devices in diameter 300 μm. Their performances are compared to the 2.5μm cut-off photodiodes with similar structures. 相似文献
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Strain Compensated AlInGaAs/InGaAs/InAs Triangular Quantum Wells for Lasing Wavelength beyond 2μm 总被引:1,自引:0,他引:1
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The subband energy and lasing wavelength of compressively strained triangular Ino.53Ga0.47As/InAs quantum well are calculated and compared with the conventional rectangular ones with the same strain contents. The strain compensation using Al0.33In0.36Ga0.31As barrier is introduced. The results show that lasing wavelength can be extended dramatically to beyond 2.8μm by changing the energy band from the conventional rectangular shape to a triangular one, the realization of such a structure using molecular beam epitaxy technology is also discussed. 相似文献
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研究了In_(0. 83)Al_(0. 17)As/In_(0. 52)Al_(0. 48)As数字递变异变缓冲层结构(DGMB)的总周期数对2. 6μm延伸波长In_(0. 83)Ga_(0. 17)As光电二极管性能的影响.实验表明,在保持总缓冲层厚度不变的情况下,通过将在InP衬底上生长的In_(0. 83)Al_(0. 17)As/In_(0. 52)Al_(0. 48)As DGMB结构的总周期数从19增加到38,其上所生长的In_(0. 83)Ga_(0. 17) As/In_(0. 83)Al_(0. 17)As光电二极管材料层的晶体质量得到了显著改善.对于在总周期数为38的DGMB上外延的In_(0. 83)Ga_(0. 17)As光电二极管,观察到其应变弛豫度增加到99. 8%,表面粗糙度降低,光致发光强度和光响应度均增强,同时暗电流水平被显著抑制.这些结果表明,随着总周期数目的增加,DGMB可以更有效地抑制穿透位错的传递并降低残余缺陷密度. 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/In 0.53 Ga 0.47 As digital alloy triangular well layers and tensile In 0.53 Ga 0.47 As/InAlGaAs digital alloy barrier layers.The x-ray diffraction and transmission electron microscope characterisations indicate that the digital alloy structures present favourable lattice quality.Photoluminescence (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 2.1 μm at 300 K and an EL signal of around 1.95 μm at 100 K have been obtained. 相似文献
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Linearly graded InxGa1-xAs metamorphic buffers with different mismatch grading rates were grown on InP substrate by gas source molecular beam epitaxy.Room temperature photoluminescence spectra show that the sample with lower mismatch grading rate in the buffer has stronger photoluminescence signal,indicating the improved optical property.Atomic force microscope images show that the lower mismatch grading rate in the buffer leads to a slightly rougher surface.The relaxation procedure with two steps in the buffer layers has been observed by X-ray diffraction reciprocal space mapping.The measurements of X-ray diffraction also reveal that the lower mismatch grading rate in the buffer is beneficial for the lattice relaxation and release of residual strain.To further increase the relaxation degree,a lower mismatch grading rate and composition "overshoot" are suggested. 相似文献