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利用固源分子束外延技术,在In0.15Ga0.85As/GaAs量子阱生长了两个InAs/In0.15Ga0.85As量子点(DWELL)样品.通过改变其中一个InAs DWELL样品中的In0.15Ga0.85As阱层的厚度和生长温度,获得了量子点尺寸增大而且尺寸分布更均匀的结果.结合光致发光光谱(PL)和压电调制光谱(PzR)实验结果,发现该样品量子点的光学性质也同时得到
关键词:
合金分解效应
0.15Ga0.85As量子点')" href="#">InAs/In0.15Ga0.85As量子点
光致发光光谱
压电调制光谱 相似文献
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研究了低温(15K)和强磁场(0—13T)条件下, InP基In053Ga047As/In052Al048As量子阱中电子占据两个子带时填充因子随磁场的变化规律.结果表明,在电子自旋分裂能远小于朗道能级展宽的情况下,如果两个子带分裂能是朗道分裂能的整数倍时,即ΔE21=kωc(其中k为整数),填充因子为偶数;当两个子带分裂能为朗道分裂能的半奇数倍时,即ΔE21=(2k+1)ωc/2,填充因子出现奇数.
关键词:
053Ga047As/In052Al048As量子阱')" href="#">In053Ga047As/In052Al048As量子阱
填充因子
磁输运 相似文献
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分别采用二种不同方法测量分子束外延(MBE)生长GaAs/In0.2Ga0.8As单量子阱结构的导带不连续量ΔEc:1) 考虑样品界面电荷修正的电容-电压(C-V)分布;2) 量子阱载流子热发射产生的电容瞬态(DLTS).C-V测得的ΔEc=0.227eV,大约相当于89% ΔEg.DLTS测得的ΔEc=0.229eV,大约相当于89.9% ΔEg.结果
关键词: 相似文献
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报道了调制掺杂的应变In0.60Ga0.40As/In0.52Al0.48As多量子阱中室温光致发光光谱.观察到n=1和2电子子带到n=1重空穴子带的强发光峰.在低温下可以观察到n=1电子子带到n=1轻空穴弱发光肩胛.通过对发光强度随激发功率及温度依赖关系以及理论模型的分析研究,认为该调制掺杂量子阱中辐射复合效率降低的主要机制是应变失配位错对载流子的陷阱作用.界面上的失配位错是陷阱的主要来源.并用静态的光致发光理论模型
关键词: 相似文献
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研究了基于InP基的In0.65Ga0.35As/In0.52Al0.48As赝型高迁移率晶体管材料中纵向磁电阻的Shubnikov-de Haas(SdH)振荡效应和霍耳效应,通过对纵向磁电阻SdH振荡的快速傅里叶变换分析,获得了各子带电子的浓度,并因此求得了各子带能级相对于费米能级的位置.联立求解Schrdinger方程和Poisson方程,自洽计算了样品的导带形状、载流子浓度分布以及各子带能级和费米能级位置.理论计算和实验结果很好符合.实验和理论计算均表明,势垒层的掺杂电子几乎全部转移到了量子阱中,转移率在95%以上.
关键词:
SdH振荡
二维电子气
FFT分析
自洽计算 相似文献
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用薛定谔方程和泊松方程自洽计算的方法研究了Al0.75Ga0.25N/GaN对称双量子阱(DQWs)中子带间跃迁(ISBT)的波长和吸收系数对中间耦合势垒高度、中间耦合势垒宽度、势阱宽度和势垒掺杂浓度的依赖关系.研究发现,第一奇序子带S1ood与第二偶序子带S2even ISBT波长随着中间耦合势垒高度的降低而变短.当中间耦合势垒高度高于0.62 eV时,S1odd<
关键词:
自洽
xGa1-xN/GaN双量子阱')" href="#">AlxGa1-xN/GaN双量子阱
子带间跃迁 相似文献
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为了提高852 nm半导体激光器的温度稳定性,理论计算了InGaAlAs、InGaAsP、InGaAs和GaAs量子阱的增益,模拟对比并研究了不同量子阱的增益峰值和峰值波长随温度的漂移。结果显示,采用In0.15Ga0.74-Al0.11As作为852 nm半导体激光器的量子阱可以使器件同时具有较高的增益峰值和良好的温度稳定性。使用金属有机化学气相沉积(MOCVD)外延生长了压应变In0.15Ga0.74Al0.11As单量子阱852 nm半导体激光器,实验测得波长随温度漂移的数值为0.256 nm/K,实验测试结果验证了理论计算结果。 相似文献
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报道了具有2,3个量子阱的In1-x1Gax1Asy1P1-y1/In1-x2Gax2Asy2P1-y2/InP张应变量子阱材料的光致荧光谱和X射线双晶衍射摇
关键词: 相似文献
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R. Kudrawiec P. Podemski M. Motyka J. Misiewicz J. Seraficzuk A. Somers J.P. Reithmaier A. Forchel 《Superlattices and Microstructures》2009,46(3):425-434
In0.53Ga0.47As/In0.53Ga0.23Al0.24As quantum wells (QWs) of various widths have been grown by molecular beam epitaxy on the InP substrate and investigated by electromodulation spectroscopy, i.e. photoreflectance (PR) and contactless electroreflectance (CER). The optical transitions related to the QW barrier and the QW ground and excited states have been clearly observed in PR and CER spectra. The experimental QW transition energies have been compared with theoretical predictions based on an effective mass formalism model. A good agreement between experimental data and theoretical calculations has been observed when the conduction band offset for the In0.53Ga0.47As/In0.53Ga0.23Al0.24As interface equals 60%. In addition, it has been concluded that the conduction band offset for the In0.53Ga0.23Al0.24As/InP interface is close to zero. The obtained results show that InGa(Al)As alloys are very promising materials in the band gap engineering for structures grown on InP substrate. 相似文献
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E.M. Goldys H.Y. Zuo T.L. Tansley M.R. Phillips C.M. Contessa 《Superlattices and Microstructures》1998,23(6):1223-1226
Photoluminescence and cathodoluminescence measurements of strained undoped In0.15Ga0.85As/GaAs and In0.15Ga0.85As/Al0.15Ga0.85As quantum well structures with emission lines attributed to the first electron–first heavy hole and first electron–first light hole excitonic transitions have been analysed theoretically within the eight-band effective mass approximation. For In0.15Ga0.85As/GaAs the results are consistent with either type I or type II alignment of the light hole band. In the case of In0.15Ga0.85As/Al0.15Ga0.85As our results indicate type II alignment for the light hole band and offset ratio ofQ = 0.83. 相似文献
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《Solid State Communications》1987,64(3):379-382
The excitonic transitions between the ground electron and hole quantum well sublevels in strained InxGa1-xAs-AlyGa1-yAs multiple quantum well structures (x = 0.12−0.35 and y = 0.2−0.35) have been investigated by means of photoluminescence and photoconductivity measurements. The molecular beam epitaxy grown structures contained an AlyGa1-yAs matrix with one unstrained GaAs and three strained InxGa1-xAs quantum wells one of which was in the GaAs cladding layers. The ratio of the conduction band edhe line up to the band gap offset for the strained InxGa1-xAs-unstrained AlyGa1-yAs interface has been found to be 0.67 ± 0.08 for the studied regions of x and y. 相似文献
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Abstract Measurements of the photoluminescence (PL) of strained In0.2Ga0.8As/GaAs and In0.15Ga0.85As/GaAs quantum well structures together with the PL from bulk GaAs, in a diamond anvil cell show that the pressure coefficient of the ground confined state in the wells depends upon well width (LZ). In the thinnest wells, the coefficient is closer to that of the bulk GaAs (10.7 meV/kbar), as expected. However, in the widest wells the coefficients tend to values (9.5meV/kbar for the 15% alloy and 9.1meV/kbar for the 20% alloy) that are significantly lower than the pressure coefficient of unstrained In0.53Ga0.47As (10.9meV/kbar). It is found that the low pressure coefficients can not be explained by the change in uniaxial stress with pressure due to a difference in bulk moduli between the barrier and well. 相似文献
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x 《Superlattices and Microstructures》1999,26(6):377
The effects of strain on the Stokes shift in one-side modulation-dopedGaxIn1 − xAs /InP asymmetric quantum wells (AQWs) are systematically investigated. By making use of a self-consistent Poisson–Schrödinger solver in the frame of a finite difference method, the quasi-Fermi levels and the band bending are determined under the effective mass approximation. The central-zone valence-band structures for compressively strained and tensile strained AQWs were calculated by making use of a four-band Luttinger–Kohn Hamiltonian. It was found that the strain influences the relative positions of the heavy-hole HH1and the light-hole LH1subbands and that the Stokes shifts are greatly reduced by tensile strain in the case of a Ga0.6In0.4As /InP AQW. Moreover, it was found that due to the presence of the two-dimensional electron gas the Stokes shifts in AQWs are much larger than the corresponding ones for a square quantum well. Also, the variation of the Stokes shift with spacer layer width for compressively strained AQWs was found to be more rapid than that for tensile strained AQWs. 相似文献
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Influence of Ga(Al)As substrates on surface morphology and critical thickness of InGaAs quantum dots
《Current Applied Physics》2019,19(5):557-562
Influence of Ga(Al)As substrates on surface morphology of InGaAs quantum dots and critical thickness of In0.5Ga0.5As film grown by molecular beam epitaxy is investigated. The In0.5Ga0.5As quantum dots are grown on (001) surfaces of GaAs and Al0.25Ga0.75 A at 450 °C, scanning tunneling microscope images show that the size of quantum dots varied slightly for 10 ML of In0.5Ga0.5As grown on GaAs and Al0.25Ga0.75As surfaces. Reflection high energy electron diffraction (RHEED) is used to monitor the growth of 4 monolayers (ML) In0.5Ga0.5As on Al0.25Ga0.75As and GaAs surfaces during deposition. The critical thickness is theoretically calculated by adding energy caused by surface roughness and heat from substrate. The calculations show that the critical thickness of In0.5Ga0.5As grown on GaAs and Al0.25Ga0.75As are 3.2 ML and 3.8 ML, respectively. The theoretical calculation agrees with the experimental results. 相似文献