重掺杂硅费米能级和少数载流子浓度的温度特性分析

费米能级和少数载流子浓度是硅半导体的重要物理参数，它们与半导体掺杂杂质种类、掺杂浓度和温度都密切相关，至今尚未有一统一的数学模型，特别是在杂质重掺杂各件下进行定量的计算。本考虑了重掺杂引起的禁带变窄效应，建立了从７７Ｋ到３００Ｋ广为适应的数学模型，着重分析了重掺杂条件下它们的温度特性，获得的计算结果与献数据较好吻合，这为低温半导体器的设计提供了有益的理论基础。     

单一杂质半导体费米能级的普适公式

利用电中性条件，导出了掺单一杂质半导体费米能级的谱适公式，在具体应用时可作相应简化。     

非简并半导体中汤姆孙效应的量子统计表示

考虑到非简化半导体中载流子的能量是温度的函数，给出了非简并半导体中的汤姆孙系数，汤姆孙电动势和汤姆孙热的更附合实际的量子统计表示，揭示了半导体中汤姆孙效应的微观机理。     

一种由自由电子能带模型计算费米能级的方法

对面心立方（fcc)、体心立方（bcc)和六角密堆积（hcp)三种不同结构的晶体,在假设它们的原胞中包含8个价电子并将价电子近似为自由电子的情况下,采用“自由电子气理论”和“自由电子能带模型”,研究其根据费米球确定的费米能级EF与根据自由电子能带模型计算的平均键能Em。研究结果表明,由自由电子能带模型计算所得3种不同结构晶体（因而电子密度也不一样）的平均键能Em等于各自自由电子系统的费米能级EF。平均键能Em是我们在异质结带阶理论计算中建议的一种参考能级,研究结果在深化对平均键能Em物理实质认识的同时,提供了一种借助于自由电子能带模型计算自由电子系统费米能级EF的新方法。     

用近简并三波混频研究半导体掺杂玻璃的非谐振三阶非线性

用近简并三波混频实验方法对半导体CdS_0.4Se_0.6掺杂玻璃在非谐振透明区的三阶光学非线性进行了研究.该实验消除了由于双光子吸收光生载流子的非线性折射产生的五阶非线性效应,仅获得速度快的三阶光学非线性响应.研究结果表明,在非谐振透明区,CdS_0.4Se_0.6掺杂玻璃的三阶非线性极化率并不比它的基底玻璃大很多.量子尺寸效应没有有意义地提高掺杂玻璃中CdS_0.4Se_0.6微晶的三阶非线性极化率,即使较小激子吸收峰的出现也没有发现明显的变化.     

n维简并理想费米气体的化学势和热容量

对能谱为ε＝ａｐ＾３的ｎ维简并理想费米气作了统一讨论，给出它的费米能、有限温度下的化学势、内能以及热容量的表达式。     

基于间接跃迁模型的p+-GaAsSb费米能级研究

重p型掺杂GaAsSb广泛应用于InP HBT基区材料,重掺杂影响GaAsSb材料的带隙和费米能级等重要参数,这些参数对设计高性能HBT起着关键作用。本文通过间接跃迁模型研究了p⁺-GaAsSb材料的荧光性质,以及费米能级与Sb组分的关系。由于费米能级与空穴有效质量m_h和空穴态密度n_h存在函数关系,我们通过荧光测量并计算了空穴有效质量m_h和空穴态密度n_h,研究结果表明m_h和n_h共同主导了费米能级的变化。     

半导体光放大器中非简并四波混频效应的理论分析

对半导体光放大器有源区中的非简并四波混频(NDFWM)过程的几种主要物理机制进行了理论分析与数值计算.由载流子速率方程、密度矩阵方程及非线性波动方程出发,分别考虑产生NDFWM效应的三个主要的物理过程：载流子浓度调制(CDP),载流子热效应(CH)及光谱烧孔效应(SHB),理论推导得其各自相应的非线性耦合波方程组,并将三种物理机制对NDFWM的贡献进行了比较,同时还讨论了线宽增强因子对NDFWM的转换效率的影响. 关键词：     

Quasiclassical calculation of the fermi level and of the forbidden energy band narrowing in crystal semiconductors with heavy doping

In an effective-mass approximation it is shown that in a heavily doped slightly compensated crystal the narrowing of the band ΔE_g>0 on complete ionization of the impurity is equal to the sum of the exchange interaction ΔE_g ^(exc) of the majority charge carriers and of the energy of the correlation interaction ΔE_g ^(cor) of a nonequilibrium minority charge carrier with a screening cloud of majority ones. When the mean-square fluctuation of the potential energy of an electron (hole) is much higher than the thermal energy, the approximation ΔE_g/E_B=1.3(Na_B ³/v)^0.58+2.7(Na_B ³/v)^0.23 is obtained, where v is the number of equivalent energy minima (valleys) at different values of the quasimomentum of the majority charge carriers, are the Bohr energy and radius; ε is the dielectric permittivity of the crystal lattice; m is the effective mass of the state density in one valley; N is the concentration of the doping impurity. The values of ΔE_g and of the high-energy edge of the interband radiating recombination calculated by the model suggested agree with the data on low-temperature photoluminescence of n-Si, p-Si, p-GaAs, and p-GaSb for 3·10⁻³<Na_B ³<2. Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 367–373, May–June, 1997.     

Energy level alignment of blended organic semiconductors and electrodes at the interface

The energy level alignment of a blended mixture of organic semiconductors is often depicted as having a common vacuum level. However, this is not a universal phenomenon among the vast number of organic semiconductors that currently exist, as in many cases the energy levels align via the Fermi level. In this report, the energy level alignments of the mixtures; poly(9-vinylcarbazole) (PVK) and 2,7-bis(diphenylphosphoryl)-9,9′-spirobifluorene (SPPO13) and poly(3-hexylthiophene-2,5-diyl) (P3HT) and SPPO13, with varying SPPO13 concentrations, are measured. It was found that the blended systems exhibit two different vacuum levels with the dipole between the PVK and SPPO13 increasing with the SPPO13 concentration, whilst the P3HT and SPPO13 vacuum levels only experience a small change. This is attributed to the decreasing electronic screening with increasing SPPO13 concentration. These new observations have an important implication in our understanding of interfacial behaviour for blended systems commonly used in various organic electronic devices.     

Direct observation of the hysteretic Fermi level modulation in monolayer MoS2 field effect transistors

The hysteresis in the transfer curve of MoS₂ has significant impact on the device performance. However, the hysteresis mechanism is still not clear. Here, we investigate the hysteresis of the monolayer MoS₂ by probing the local Fermi level variations as a function of the back gate voltage in different atmosphere using the Kelvin probe microscopy. While the Fermi level of the MoS₂ in air is much lower than that in vacuum, both the MoS₂ devices in vacuum and air show large Fermi level hysteresis. The Fermi level hysteresis direction is clock-wise, identical to that observed in the transfer curves. Both the hysteresis in Fermi level and transfer curve can be explained consistently by taking into account the charge trapping. Our findings confirm that carrier density modulation in MoS₂ plays a vital role in the hysteresis, and provide insight into the hysteresis mechanism for the optimization of the device performance.     

A study of Fermi level shifts in copper-gallium and copper-germanium alloys by x-ray absorption spectroscopy

The K x-ray absorption discontinuities of copper, gallium and germanium in pure metals as well as in six copper-gallium and three copper-germanium alloys have been studied using a Cauchois-type bent crystal spectrograph. It is observed that in all the systems the K discontinuity of copper shifts towards the higher energy side, while the discontinuities of gallium and germanium shift to the lower energy side relative to their positions in the respective pure metals. The magnitudes of the shifts are found to increase with the decrease in the content of the absorbing atom in the alloys. The observed shifts are explained on the basis of the free-electron theory of metals and the rigid-band model for alloys.     

用正电子湮没多普勒增宽谱测量金属中电子的费米能级

高校中不少实验室具有半导体探头能谱仪,可扩展用作正电子湮没多普勒增宽谱仪,并测量金属中电子的费米能级     

A comment concerning the monotonous shift of the Fermi level with increasing temperature in semiconductors

The shift of the Fermi energy E_F with the temperature is analyzed for extrinsic semiconductors as a function of the compensation. Some limiting conditions are given for E_F shifting monotonously with temperature.     

费米共振对分子振动能级和光谱的影响

费米共振相互作用对多原子分子具有相同对称类的近简并振动能级及其光谱产生影响,利用定态微扰理论,分析了五阶近似下费米共振对三个振动能级的影响,应用于CO2分子的(0400),(1200)和(2000)三个近简并能级,计算结果与实验观测值符合较好,并讨论了费米共振对(0400),(1200)和(2000)向(0110)能级跃迁时光谱线强度的影响.     

Asphericity in the Fermi Surface and Fermi Energy of Na-K, Na-Rb and Na-Cs Binary Alloys

Detailed theoretical investigations into asphericity in the Fermi surface (FS) and Fermi energy (FE) ofNa1_xKx, Na1_xRbx, and Na1_xCsx binary solid solutions are carried out for the first time. The alloying behavior ofthe K, Rb, and Cs with the Na generates the Fermi surface distortion (FSD) of bce simple metals. The FS of Na-K,Na-Rb, and Na-Cs solid solution is a distorted sphere with the largest deviation along [110]. We have found that theimpact of local-field correction function on FSD is maximun at [100] point and minimum at [111] point. The exchangeand correlation effect is found to suppress the value of FE.