Hg1—xCdxTe表面电子的子能带结构

讨论了Hg_(1-x)Cd_xTe MIS结构N型反型层电子子能带结构的理论和实验研究结果。描述了采用电容-电压谱,回旋共振谱和磁导振荡谱定量地研究电子子能带结构的模型和方法。推导得到的子能带色散关系,朗道能级和有效g~*因子,与测得的子能带电子的回旋共振和自旋共振结果符合得很好,从而可以定量地研究由于表面电子的自旋轨道相互作用引起的零场分裂效应,朗道能级的移动、交叉,波函数的混合效应以及电致自旋分裂的色散关系。     

HgGdTe子能带电子的磁光共振

报道P-Hg_(1-x)Cd_xTe(x=0.234、N_A=4×10~(17)cm~(-3))MIS结构样品在电量子限条件下电子子能带朗道能级间磁光共振光跃迁实验结果。测量了不同光子能量和样品在不同表面电子浓度时子能带朗道能级间和自旋能级间的回旋共振和自旋共振。定量地证明了窄禁带半导体量子阱子能带朗道能级的移动和交叉效应,这一效应起源于表面势的反演不对称所导致的较强的表面电子自旋轨道相互作用。     

GaAs／AlGaAs异质结中二维电子气的回旋共振研究

采用栅压比谱的方法，研究了ＧａＡｓ／ＡｌＧａＡｓ异质结中二维电子气（２ＤＥＧ）的回旋共振。观察到由于子能带－朗道能级耦合所引起的回旋共振峰强度随磁场的振荡行为．由回旋共振频率ωｃ确定了子能带电子的回旋共振有效质量ｍ＊，通过对共振峰线形的拟合，获得二维电子气浓度Ｎｓ、电子散射时间τ和迁移率μ．由子能带－朗道能级的共振耦合测量了不同栅压下的多个子能带间的能量间距．讨论了导带非线抛物性对电子回旋共振有效质量的影响     

P－型HgCdTe MIS结构反型层激发态子能带结构研究

本文在４．２Ｋ下获得了Ｐ－型ＨｇＣｄＴｅ反型层有两个子能带被占据时的电容谱．基于多个子带被占据的非量子限情形，提出了一个实验模型．用该模型对实验结果进行了拟合，获得了反型层基态及激发态子能带结构，包括基态子能带能量、第一激发态子能带能量、费米能级、耗尽层厚度、反型层平均厚度以及它们随反型层电子浓度的变化关系．     

Hg_(1-x)Cd_xTe反型层子能带结构的实验研究

本文在4.2K下测定了液相外延HgCdTe MIS结构样品的电容谱,磁阻振荡以及迴旋共振效应,并从实验测量结果,采用物理参数拟合法,确定了该样品在电量子限条件下反型层电子子能带结构,包括基态子能带能量E_o、费密能级E_F,子能带电子有效质量m~*(E_F)、m~*(E_o)、反型层平均厚度Z_i、耗尽层厚度Z_d,以及它们随子能带电子浓度N_s的变化。     

InSb带间磁光吸收

本文介绍利用连续运行的 CO 激光器观察了 InSb 的带间磁光吸收,不同朗道能级间的跃迁形成了一系列的吸收峰值,最低的四个带间跃迁是与导带朗道能级的自旋向上(0↑)和自旋向下(0↓)以及施主杂质能级的跃迁有关。     

在外磁场作用下Rashba系统中的磁光吸收谱

基于半经典玻尔兹曼方程的方法研究了InGaAs/InAlAs 系统中电子在Rashba自旋轨道耦合相互作用(RSOI)和外磁场作用下二维电子气(2DEG)的磁光吸收谱以及选择定则。RSOI的存在使朗道能级相互混合并移动, 在高迁移率和强磁场条件下, 磁光吸收谱可以观察到来自相邻郎道能级和相同自旋间的两个主吸收峰。随着电子浓度、外磁场以及自旋轨道耦合强度的不同可以相应地调制吸收谱强度和峰位等。另外, 由于朗道能级的混合, 使磁光谱出现自旋反转的跃迁, 但由于不同自旋态的电子波函数的重叠很小, 此跃迁对磁光吸收谱的贡献很小。     

利用双势垒结构研究磁场下二维电子的态密度

势垒结构磁电容曲线，测量了垂直磁场下二维电子态密度。采用高斯型朗道态密度模型计算了双势垒结构的电容随磁场的变化曲线，与不同偏压和温度下的实验曲线符合得相当好，由此得到朗道能级模型态密度。根据拟合自洽地给出了二维浓度、费密能级、子带能量和有效Ｌａｎｄｅ因子随场振荡变化的规律。     

Cr掺杂纤锌矿GaN的磁性和光学性质

采用自旋极化密度泛函理论方法,对Cr掺杂纤锌矿GaN的能带结构和态密度进行计算,通过计算的能带结构和光学线性响应函数,系统讨论了Cr掺杂对纤锌矿GaN电子结构、磁学和光学属性的影响。计算结果显示:Cr掺杂纤锌矿GaN的反铁磁态具有半金属特征,铁磁态具有金属特性和磁性,磁矩主要源于费米能级附近的Cr 3d和N 2p能带发生劈裂导致自旋向上和自旋向下的电子的态密度不同所致。光学性质计算结果显示,Cr掺杂纤锌矿GaN的费米能级附近出现极大的介电峰,具有优异的发光性能,峰值对应于紫外波段,在高能区吸收峰发生了红移现象,在低能区红外波吸收增强。理论计算表明,Cr掺杂纤锌矿GaN可能是一种性能优异的磁光材料。     

抛物线型势阱二维电子气能级的解析解

从玻尔 -索末菲量子化条件出发 ,以抛物线势阱为模型 ,建立了硅 MOS结构表面反型层中二维电子气能级 E满足的超越方程 ,并从该方程得到了能级 E的解析表达式。该式能够非常简单地确定出抛物线型势阱中的能级 ,而不需要数值求解薛定谔方程     

非量子限条件下P型InSbMOS结构反型层中子能带实验研究

在100K条件下测量了p型InSb MOS器件的变频电容-电压(C-V)谱,在反型区观察到第二子带填充电子的台阶效应,还发现一个位于导带中的共振缺陷态.采用非量子限多带C-V拟合模型获得了子能带结构.     

HgCdTe-MISFET fabrication with multi-step surface passivation and quantum effects

We have used multi-step surface passivation process integrating electrochemical reduction and UV exposure with native sulfidization by H₂S gas to obtain high quality ZnS/p-HgCdTe interface. It shows very low parasitic interface charge density of the order of 10¹⁰cm⁻². The insulating ZnS layer also exhibits very high resistivity of ∼10¹² Θcm. The resulting fabricated HgCdTe-MISFETs show 2D quantum effects. Magnetoresistance measured at 1.5K displays oscillations which begin to appear above the gate voltage of 10V. They are identified as the Shubnikov-de Haas oscillations involving three electronic subbands. The magnetotransport data are quantitatively analyzed with the calculated Landau level-fan diagram and confirm the 2D subband quantization of the inversion layer at the ZnS/p-HgCdTe interface. This result demonstrates successful role of the multi-step surface passivation for realizing 2D ZnS/HgCdTe interface which will provide high quality 2DEG resevoir basis in future Hg-based narrow-gap nanostructure device applications.     

Six-band k·p approach to the effects of doping on energydispersion in p-type strained In0.15Ga0.85As-Al0.33Ga0.67As quantum-well structures

We report an application of the six-band Luttinger-Kohn model to the subband energy dispersions in the valence band for the p-type In_0.15Ga_0.85As-Al_0.33Ga_0.67 As quantum-well (QW) structures. It was found that, in addition to the contentional biaxial compressive strain related to the lattice constant and well width of the structures, the p-type doping also caused a shift of the subband energy levels in the valence band by varying the barrier height. It was also found that the strain of the QW structures was not a constant but was sensitive to the p-type doping density, which also induced the shift of the subband energy levels. The calculated results, based on intersubband transitions of the heavy holes and taking the doping-related changes in strain and barrier height into account, were in good agreement with the experimental data, measured using Fourier transform infrared technique     

SiC半导体二维自旋磁极化子能量的磁场效应

在考虑声子之间相互作用和电子自旋的情况下,应用么正变换和线性组合算符法研究了电子自旋对SiC半导体弱耦合二维自旋磁极化子能量磁场效应的影响。数值计算给出了下列结果:电子自旋使自陷能分裂为二,且随磁场B增加其分裂间距增大;电子自旋能量与电子在磁场中的Landau基态能之比恒为0.23;电子自旋能量与自能之比小于电子自旋能量与自陷能之比,但非常接近,它们随B增强而近似线性增大,当B为0和10T时,它们分别为0和0.008;电子自旋能量与声子之间相互作用能量之比也随B增加而线性增大,当B为0和7.949T时,其比值分别为0和1。该结果有助于设计和研制自旋场效应晶体管,自旋发光二极管和自旋共振隧道器件等。     

Spin splitting and electron g-factor of an excited quantum confinement subband

The spin splitting of the zeroth Landau level is observed in the oscillations of the magnetoresistance of an Al_0.28Ga_0.72As:Si/GaAs heterostructure for the upper quantum-confinement subband with the bottom energy E _p . This effect is related to intersubband electron transitions from the lowest ground E _m confinement subband to the states of the upper E _p subband depopulated by the magnetic field. The spectroscopic splitting factor for the electrons of the E _p subband is found: |g| = 8.2?12.2 for the concentrations in the range n _p = (0.52?1.04) × 10¹¹ cm^?2.     

C-VCharacterization in MOS Structure Inversion Layer Including Quantum Mechanical Effects

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C-VCharacterization in MOS Structure Inversion Layer Including Quantum Mechanical Effects

A simplified method to calculate the band bending and subband energy is presented to investigate the Quantum Mechanical Effects (QMEs) in MOS structure inversion layer. The method is fairly unique compared with the published methods in the reversed nature of the iteration procedure. It has high efficiency and good convergence characteristics. Gate capacitance in MOS structure inversion region is formulated in both quantum mechanical cases and semi-classical cases and Quantum Mechanical Effects on gate capacitance have been analyzed. Results of different substrate doping levels are compared and the substrate doping concentration dependence of QMEs on gate capacitance is studied. It is shown that QMEs lead to a substantial decrease in gate capacitance in the strong inversion region. Results of different substrate doping levels indicate that the QMEs on gate capacitance are different substantially in the threshold region at different substrate doping levels but almost the same in the strong inversion region.     

平行磁场下半导体超晶格电子结构(英文)

Electron and hole subbands of superlattices in an in-plane magnetic field are investigated. Landau energy levels, subband dispersion curves and optical transition probabilities in GaAs-AlxGa1-xAs are calculated by using the effective mass theory. The variations of the binding energies of light and heavy hole excitoas as functions of quantum well width and magnetic field strength are obtained.Electronic energy levels in a magnetic field (in xy plane) with the tilting away from the growth direction (y axis) are calculated and discussed.