共查询到19条相似文献,搜索用时 531 毫秒
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系统地研究了波长为2.7μm的InGaAsSb/AlGaAsSb多量子阱激光器中有源区的优化设计.分别用含应变势的6带KP模型和抛物带模型计算价带和导带的能带结构,并得到薛定谔方程和泊松方程的自洽解,由此计算量子阱在载流子注入时的增益谱.研究表明制约量子阱增益的主要因素不是跃迁矩阵元,而是粒子数反转程度,尤其是空穴填充HH1子带的概率.增加压应变或减小阱宽都会提高量子阱增益.前者降低了价带HH1子带空穴的平面内有效质量;后者拉大了价带子带间距,尽管它同时略微增加了空穴有效质量.这两种因素都导致价带顶空穴态 相似文献
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系统地研究了波长为2.7μm的InGaAsSb/AlGaAsSb多量子阱激光器中有源区的优化设计,分别用含应变势的6带KP模型和抛物带模型计算价带和导带的能带结构,并得到薛定谔方程和泊松方程的自洽解,由此计算量子阱在载流子注入时的增益谱,研究表明制约量子阱增益的主要因素不是跃迁矩阵元,而是粒子数反转程度,尤其是空穴填充HHl子带的概率,增加压应变或减小阱宽都会提高量子阱增益,前者降低了价带HHl子带空穴的平面内有效质量;后者拉大了价带子带间距,尽管它同时略微增加了空穴有效质量,这两种因素都导致价带顶空穴态密度的降低,提高了空穴在HHl子带的填充概率,最终提高了量子阱的增益,所得结论与已有的实验报道相符。 相似文献
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报道了压电调制反射测量系统的建立,应用该系统获得了势阱宽度分别为5nm和25nm的两个G aAs/Al0.29Ga0.71As单量子阱的压电调制反射谱. 从图谱中可以看 出,在室 温下能够较容易地分辨出和轻、重空穴相关联的子带跃迁. 在阱宽25nm的样品中还观察到了 自旋-轨道跃迁. 利用有效质量理论近似计算,对量子阱样品的图谱结构进行了指认,发现 实验值和计算值能够较好地符合.
关键词:
压电调制反射光谱
单量子阱
分子束外延 相似文献
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通过测量GeSi多量子阱的红外谱,同时观察到了相应于量子阱内重空穴基态HH1到重空穴激发态HH1、轻空穴激发态LH1和自旋分裂带SO及连续态间的跃迁吸收.测量了GeSi多量子阱探测器的正入射光电流谱,看到了明显的光响应峰.理论计算中计及了轻、重和自旋分裂带间的耦合及能带的非抛物性,并自洽考虑了哈特里势和交换相关势.与实验结果比较,认为带之间的耦合,使子带间的跃迁情况变得复杂,是正入射吸收产生的原因
关键词: 相似文献
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张应变GaAs_(1-x)P_x量子阱是高性能大功率半导体激光器的核心有源区,基于能带结构分析优化其结构参数具有重要的应用指导意义.首先,基于6×6 Luttinger-Kohn模型,采用有限差分法计算了张应变GaAs_(1-x)P_x量子阱的能带结构,得到了第一子带间跃迁波长固定为近800 nm时的阱宽-阱组分关系,即随着阱组分x的增加,需同时增大阱宽,且阱宽较大时靠近价带顶的是轻空穴第一子带lh_1,阱宽较小时靠近价带顶的是重空穴第一子带hh_1.计算并分析了导带第一子带c_1到价带子带lh_1和hh_1的跃迁动量矩阵元.针对808 nm量子阱激光器,模拟计算了阈值增益与阱宽的关系,得到大阱宽有利于横磁模激射,小阱宽有利于横电模激射.进一步考虑了自发辐射和俄歇复合之后,模拟计算了808 nm量子阱激光器的阱宽与阈值电流密度的关系,阱宽较大时载流子对高能级子带的填充使得阈值电流密度增加,而阱宽较小时则是低的有源区光限制因子导致阈值电流密度升高,因此存在一最佳的阱宽-阱组分组合,可使阈值电流密度达到最小.本文的模拟结果可对张应变GaAs_(1-x)P_x量子阱激光器的理论分析和结构设计提供理论指导. 相似文献
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张应变GaAs1-xPx量子阱是高性能大功率半导体激光器的核心有源区,基于能带结构分析优化其结构参数具有重要的应用指导意义.首先,基于6×6 Luttinger-Kohn模型,采用有限差分法计算了张应变GaAs1-xPx量子阱的能带结构,得到了第一子带间跃迁波长固定为近800 nm时的阱宽-阱组分关系,即随着阱组分x的增加,需同时增大阱宽,且阱宽较大时靠近价带顶的是轻空穴第一子带lh1,阱宽较小时靠近价带顶的是重空穴第一子带hh1.计算并分析了导带第一子带c1到价带子带lh1和hh1的跃迁动量矩阵元.针对808 nm量子阱激光器,模拟计算了阈值增益与阱宽的关系,得到大阱宽有利于横磁模激射,小阱宽有利于横电模激射.进一步考虑了自发辐射和俄歇复合之后,模拟计算了808 nm量子阱激光器的阱宽与阈值电流密度的关系,阱宽较大时载流子对高能级子带的填充使得阈值电流密度增加,而阱宽较小时则是低的有源区光限制因子导致阈值电流密度升高,因此存在一最佳的阱宽-阱组分组合,可使阈值电流密度达到最小.本文的模拟结果可对张应变GaAs1-xPx量子阱激光器的理论分析和结构设计提供理论指导. 相似文献
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Microwave magnetoresistance of lightly doped (nondegenerate) p‐Ge has been studied by the electron spin resonance method, which can record the derivative of the microwave absorption with respect to the magnetic field. The change in the absorption is proportional to that in the conductivity of the semiconductor in the magnetic field (magnetoresistance). It was found that the averaging time of the light and heavy holes effective masses depends on temperature and on the magnetic field direction in a sample. An analysis of the derivative made it possible to determine regions of the fastest effective mass averaging. 相似文献
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Temperature variation of the magneto-microwave Kerr effect, in the range 130–430 K, has been studied in two high conductivity samples of p-Ge at a magnetic field of 0.3 Wb m?2 using a K-band double microwave bridge. The experimental results have been analysed by considering the impurity, acoustic phonon and non-polar optical phonon scatterings. It is found that all the three scatterings play an important role in the present range of temperature. In this temperature range the effective masses of the light and heavy holes are found to be independent of temperature. 相似文献
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V. A. Kukushkin 《Physics of the Solid State》2009,51(9):1821-1827
A method is proposed for generating terahertz radiation by producing a spectrally limited population inversion between light-
and heavy-hole subbands in the valence band of semiconductors. This inversion is achieved by placing a sample in a static
magnetic field and pumping it with an alternating electric field resonant with a cyclotron frequency of heavy holes. At a
sufficiently low concentration of holes when the energy exchange between them is less effective than the exchange with the
lattice, a considerable heating of heavy holes occurs with a nearly constant distribution function of light holes. However,
the low hole concentration leads to a small terahertz field gain that can exceed the field loss only in high-quality diamond
samples that are almost transparent in the terahertz range. An important advantage of this method for generating terahertz
radiation over the previously proposed techniques is the possibility of implementing it at room temperature, which substantially
increases its attractiveness, especially for use in biology and medicine. 相似文献
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It is not known if the scattering probabilities of two kinds of holes in p-type gallium antimonide are the same. In the present paper we found by mobility measurements in the temperature range 77–300 K that the scattering probabilities of heavy and light holes are not the same and they depend not only on the number of the final allowed states in the band of the the heavy holes into which are scattered, but also on a reduced effective mass. 相似文献
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M. V. Entin L. I. Magarill 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,81(2):225-230
The 2D semimetal consisting of heavy holes and light electrons is studied. The consideration is based on the assumption
that electrons are quantized by magnetic field while holes remain classical. We assume also that the interaction between components
is weak and the conversion between components is absent. The kinetic equation for holes colliding with quantized electrons
is utilized. It has been stated that the inter-component friction and corresponding correction to the dissipative conductivity
σ
xx
do not vanish at zero temperature due to degeneracy of the Landau levels. This correction arises when the Fermi level crosses the Landau level. The statement
will keep in force until the degeneracy remains. The limits of kinetic equation applicability were found. We also study the
situation of kinetic memory when particles repeatedly return to their meeting points. 相似文献
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The energy distribution function of hot heavy and light holes, the degree of population inversion and of the accumulation of light holes are determined from an investigation of near infrared light absorption in crossed magnetic and electric fields. Analysis of the data shows that inversion of the population is caused not only by accumulation of light holes, but also by weaker heating of light holes compared with heavy holes and drift in momentum space. The numeral value and spectral dependence of the FIR gain, are determined. The distribution function and optical gain are in good qualitative and quantitative agreement with the values calculated by the Monte Carlo method. The power of the far-infrared laser is estimated. 相似文献
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Ya. E. Pokrovskii N. A. Khvalkovskii 《Journal of Experimental and Theoretical Physics》2013,117(4):742-746
Spontaneous emission and photoconductivity of germanium with gallium impurity are studied for determining the energy spectrum of hole states in this material in which radiation can be induced as a result of transitions of holes between these states. Holes were excited by electric field pulses with a strength up to 12 kV/cm at T = 4.2 K under uniaxial compression of samples up to 12 kbar. It has been found that hole emission spectra for transitions between resonant and local states of the impurity have a structure identical to the photoconductivity and absorption spectra. Transitions from resonance states, which are associated with the heavy hole subband, have not been detected. It has been found that in an electric field lower than 100 V/cm, a compressed crystal emits as a result of transitions of heavy holes. In a strong electric field (1–3 kV/cm), emission is observed in the energy range up to 140 meV, and transitions with emission of TA and LO phonons appear in such a field. The emission spectra under pressures of 0 and 12 kbar differ insignificantly. Hence, it follows that the contributions from heavy and light holes in a strong electric field are indistinguishable. 相似文献
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S. I. Dorozhkin 《JETP Letters》2008,88(12):819-822
Magnetoresistance measurements have been performed for the cases of one and two occupied size-quantization hole subbands in silicon field-effect transistors prepared on the Si (110) surface. In both cases, Shubnikov-de Haas oscillations exhibit very weak sensitivity to the in-plane component of the magnetic field. This indicates that both lowest subbands are formed by heavy holes. This conclusion disagrees with the wide-spread opinion that the second subband is the ground subband of light holes in the system under consideration. 相似文献
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We theoretically calculate the Josephson current for two
superconductor/ferromagnetic semiconductor (SC/FS) bilayers
separated by a semiconductor (SM) layer. It is found that the
critical Josephson current IC in the junction is strongly
determined by not only the relative orientations of the effective
exchange field
of the two bilayers and scattering
potential strengths at the interfaces but also the kinds of holes
(the heavy or light) in the two FS layers. Furthermore, a robust
approach to measuring the spin polarization P for the heavy and
light holes is presented. 相似文献