共查询到20条相似文献,搜索用时 31 毫秒
1.
The resonance enhancement of the third-order nonlinear optical susceptibility χ(3) for degenerated four-wave mixing, due to the transition between valence band and conduction band, in InGaN/GaN multi-quantum wells have been calculated. The band structures of valence bands and conduction bands and the wave functions are calculated by the theory of effective mass. The contributions of the subbands of holes (heavy holes, light holes and the spin-orbit split-off bands) to χ(3) in the different directions are discussed. The correlations between χ(3) in the different directions and the width of the quantum wells, and the constituents of the quantum wells are obtained. 相似文献
2.
《Superlattices and Microstructures》2001,29(2):91-98
Photocurrent spectra in an In0.53Ga0.47As /In0.52Al0.48As multi-quantum wells structure containing 9.4 nm wide wells were measured at room temperature in electric fields. The exciton peaks of ground-state transitions shifted fairly in 167 kV cm − 1as the quantum confined Stark effect. Stark shifts were calculated by using the Runge–Kutta method using the effective mass equation with our experimental band parameters. Our parameters are the hole effective masses and valence band offset derived from saturation of a highest eigen energy, electron effective mass depending on energies and the conduction band offset derived from observed quantum number. It was possible to sufficiently use our experimental band parameters for the calculation of the Stark shift in the electric field. 相似文献
3.
4.
Wide spectral white light emitting diodes have been designed and grown on a sapphire substrate by using a metal-organic chemical vapor deposition system. Three quantum wells with blue-light-emitting, green-light-emitting and red-light-emitting structures were grown according to the design. The surface morphology of the film was observed by using atomic force microscopy. The films were characterized by their photoluminescence measurements. X-ray diffraction θ/2θ scan spectroscopy was carried out on the multi-quantum wells. The secondary fringes of the symmetric ω/2θ X-ray diffraction scan peaks indicate that the thicknesses and the alloy compositions of the individual quantum wells are repeatable throughout the active region. The room temperature photoluminescence spectra of the structures indicate that the white light emission of the multi-quantum wells is obtained. The light spectrum covers 400-700 nm, which is almost the whole visible light spectrum. 相似文献
5.
R. Charrour D. Bria 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(1):37-44
The temperature dependence of the cyclotron resonance mass (CRM)
of the magnetopolaron in ZnCdSe/ZnSe multi-quantum wells with
strong magnetic field is investigated theoretically using the
Lee-Low-Pines variational method. The contributions to the CRM due
to the nonparabolicity of the conduction band and the coupling of
electron with both confined longitudinal optical and interface
optical phonons are considered. Results of our calculations are
compared with the experimental data, and a qualitative agreement
is found over a large temperature range. We show that these three
contributions complement each other to determine the cyclotron
mass as a function of the temperature. 相似文献
6.
《Superlattices and Microstructures》1999,26(1):17-22
We observed that a series of peaks, which were clearly extracted from a photocurrent difference spectrum, corresponded to interband optical transitions of an In0.53Ga0.47As /In0.52Al0.48As multi-quantum wells structure. The nonparabolic tendency of the electron effective mass was suggested from eigenenergies of conduction subbands. The effective mass estimated in a direction normal to the InGaAs quantum well plane was heavier than the effective mass of the bulk band edge and was 0.07 m0at the top of a quantum potential well. 相似文献
7.
从固体模型理论的结果出发,计算了生长于Si(100)衬底上x值小于085的Si1-xGex合金材料(能带结构为类Si结构)的间接带隙与应变的关系,结 果表明,应变的S iGe材料的带隙和完全弛豫状态下材料的带隙之差与应变呈线性关系.基于这一结果,提出了 用测量带隙来间接测定SiGe/Si应变状态的方法.用带隙法和x射线双晶衍射法测量了不同应 变状态下的SiGe/Si多量子阱材料的应变弛豫度,两者可以较好的符合,表明带隙法测量SiG e应变弛豫度是可行的.
关键词:
SiGe合金
应变
带隙 相似文献
8.
FENG XiaoBo LI Yan QIN Yi XIAO YunFeng YANG Hong & GONG QiHuang State Key Laboratory for Mesoscopic Physics 《中国科学:物理学 力学 天文学(英文版)》2011,(8)
We demonstrate that the femtosecond time-resolved magneto-optical Kerr rotation oscillates with the direction of polarization of the probe beam when a sample of Al0.25Ga0.75As/GaAs multi-quantum wells is excited by a circularly polarized pump and detected by a linearly polarized probe at wavelengths from 800 to 830 nm. Analytical expressions are derived to explain the mechanism, which is in good agreement with the numerical computation and the experimental data. The results suggest that the Kerr signal can ... 相似文献
9.
A quantum well intermixing process combining inductively-coupled-plasma reactive ion etching (ICP-RIE) and SiO2 sputtering film was investigated for the InGaAsP and InGaAlAs multi-quantum wells (MQWs). Optimal distance is 300-nm-thick for InGaAsP and of 200-nm-thick for InGaAlAs. Between MQWs and the upper cladding by ICP-RIE and bombardment, covering the 300-nm-thick sputtered SiO2 using rapid thermal annealer (RTA) processing resulted in a band-gap blue-shift of 90 nm for InGaAsP and of 60 nm for InGaAlAs. 相似文献
10.
《Superlattices and Microstructures》1998,24(4):255-258
Nonparabolicity of conduction subbands in nanoscale potential wells has been probed using InGaAs/InAlAs multi-quantum well structures. From cyclotron resonance absorption at a wavelength of 119 μm, the apparent mass ratio was found to be 0.061 near the bottom of the ground subband. From cyclotron resonance absorption at a wavelength of 10.6 μm, the apparent mass ratio of high-energy electrons was found to be 0.066–0.067, which was higher than the bulk bandedge mass ratio, 0.041. Evidence of the two-dimensional conduction subbands was examined by an interband absorbance spectrum. 相似文献
11.
采用射频反应磁控溅射的方法,在经过氧化处理的Al2O3(0001)基片上制备了具有良好调制结构的ZnO/MgO多层膜量子阱.利用X射线反射率测量、X射线衍射分析、电子探针显微分析、原子力显微镜、透射光谱以及光致发光光谱等表征技术,研究了ZnO/MgO多量子阱的结构、表面形貌和光致发光等特性.XRD以及扫描的结果表明多层膜样品具有高c轴择优取向并且与蓝宝石基片有良好的外延关系.通过X射线反射率测量的结果得到多量子阱的调制周期,结合电子
关键词:
ZnO/MgO
多量子阱
反应磁控溅射
变温光谱 相似文献
12.
The shot noise properties in a graphene-based multi-quantum well structure are investigated theoretically. It is found that when the number of the potential barriers (quantum wells) is big enough and the width of the barriers and the wells is shorter than the mean free path, another Dirac-like point at which the Fermi energy equals half of the barrier height appears. The transport is almost forbidden at this new Dirac-like point, the conductivity gets the minimum, and the Fano factor approaches 1/3. With the random potential barrier being taken into consideration, the conductance enhances clearly, meanwhile the Fano factor is suppressed much more. 相似文献
13.
We report an eight-channel silicon evanescent laser array operating at continuous wave under room temperature conditions using the selective-area metal bonding technique.The laser array is realized by evanescentl.y coupling the optical gain of InGaAsP multi-quantum wells to the silicon waveguides of varying widths and patterned with distributed Bragg reflector gratings.The lasers have emission peak wavelengths in a range of 1537-1543 nm with a wavelength spacing of about 1.0 nm.The thermal impedances Z_T of these hybrid lasers are evidently lower than those DFB counterparts 相似文献
14.
O. Krebs P. Voisin D. Rondi J. L. Gentner L. Goldstein J. C. Harmand 《Physica E: Low-dimensional Systems and Nanostructures》1998,2(1-4)
Due to their reduced symmetry no-common atom heterostructures are expected to present in-plane anistropic features. We report polarization-resolved optical transmission measurements performed on GaInAs–InP multi-quantum wells evidencing a large dichroïsm. A linear dependence of this anistoropy on an electric field has also been observed, giving rise to the quantum confined Pockels Effect. All these intrinsic results which are forbidden by the usual envelope function theory compare fairly well with the predictions of the recently proposed
model. 相似文献
15.
Effect of annealing on photoluminescence and microstructures of InGaN/GaN multi-quantum well with Mg-doped p-type GaN 总被引:3,自引:0,他引:3 下载免费PDF全文
InGaN/GaN multi-quantum well structure with Mg-doped p-type GaN was grown by low-pressure metalorganic vapour phase epitaxy. After rapid-thermal-annealing at 700 and 900${^\circ}$C, both the red-shift and the blue-shift of the photoluminescence (PL) peak, the decreased and the enhancement of the PL intensity were observed. The transmission electron microscopic images showed that InGaN multi-quantum-dots-like (MQD-like) structures with dimensions less than 5$\tm$10nm were formed in InGaN wells. The changes of PL spectra could be tentatively attributed to the competition between the red-shift mechanism of the quantum-confined Stark effect and the blue-shift mechanism of the quantum size effect due to MQD-like structures. 相似文献
16.
本文国内首次报道了LP-MOVPE法生长高质量的压、张应变交替InGaAsP多量子阱结构的研制过程及其材料的高精度X-ray双晶摇摆衍射曲线和荧光光谱特性表征.在此材料基础之上制作的宽接触激光器阈值电流密度小于300A/cm2(腔长800μm),平面掩埋条形结构激光器平面掩埋异质结(PBH)条形结构多量子阱激光器阈值电流13~15mA.经过双腔面镀增透射膜后,其TE模与TM模自发发射谱光强差为3dBm,呈现偏振补偿特性. 相似文献
17.
《Current Applied Physics》2002,2(5):373-378
The main problems of conventional multi-quantum well infrared photodetectors (QWIPs) were discussed. In order to overcome the limitations of the conventional QWIPs, such as small photocurrent, high dark current and low response speed, novel QWIPs in which photocurrent increases with the number of well were proposed. The novel structure with several wells were calculated and analyzed in detail, and successfully fabricated. The dark current lower than conventional QWIPs by about one order of magnitude was obtained, well in agreement with theoretical value. I–V characteristics of the novel QWIPs with six wells has been presented, and six related negative differential resistance regions were observed at positive bias. The absorption photocurrents of the novel QWIPs at 77 K were found to increase with well numbers, confirming the mechanism of the new structure. Furthermore, the transportation of the optoelectronic and some other problems of the QWIPs were discussed. 相似文献
18.
建立了一种适用于多量子阱和多有源区的多层速率方程模型. 通过小信号分析,得到了光子密度、载流子俘获、逃逸和隧穿时间等关键参数对单有源区和隧道再生双有源区垂直腔面发射激光器频率响应特性的影响,并分析了在相同驱动电流下隧道再生双有源区器件调制带宽大于单有源区器件的原因. 进一步研究了隧道再生双有源区内腔接触氧化限制型垂直腔面发射激光器的寄生电参数及其寄生电路,对其频率响应进行了模拟分析.
关键词:
垂直腔面发射激光器
速率方程
调制特性
隧道再生 相似文献
19.
利用洛伦兹线型函数、高斯线型函数和Sech线型函数对InP/InGaAsP多量子阱自发辐射谱进行拟合,采用莱文贝格-马夸特算法,得到上述三种函数的解析表达式.研究结果表明:高斯线型光谱拟合函数的中心波长为1548.651nm,谱线半极大全宽度为61.42 nm,功率补偿为0.00212 mW,拟合优度为0.99191,残差平方和为2.26505×10~(-6).高斯线型拟合的拟合优度最大,残差平方和最小,且各数据点的残差值分布在±0.0001之间,分布比较均匀.高斯线型函数具有较高拟合度. 相似文献
20.
K. Tanaka Y. Tanoue Y. Ueki K. Shibata N. Kotera M. Washima H. Nakamura 《Optical and Quantum Electronics》2002,34(7):649-659
Interband transmission spectra were measured for three In0.53Ga0.47As/In0.52Al10.48As multi-quantum well specimens having different carrier concentrations by modulation-doping. Spectral shapes of transmissions were clear steplike structures but exciton peaks of first order transitions were masked with the carrier concentrations. The spectral shapes changed hardly between 100 and 310 K. Using our parameters of quantum wells, calculated eigen-energies for three specimens agreed with experiments and absorption coefficients reproduced experimental transmission spectra at any temperature. 相似文献