Determination of the inelastic mean free path of electrons in GaAs and InP after surface cleaning by ion bombardment using elastic peak electron spectroscopy

The inelastic mean free path (IMFP) of electrons is an important material parameter needed for quantitative AES, EELS and non-destructive depth profiling. The distinction between the terms for IMFP and the attenuation length (AL) has been established by ASTM standards. A practical experimental method for determining values of the IMFP is elastic peak electron spectroscopy (EPES). In this method, experimentally determined ratios of elastically backscattered electrons from test surfaces and from a Ni reference standard are compared with the values evaluated theoretically.The present paper reports systematic measurements of the IMFP by EPES for GaAs and InP. They are carried out in two laboratories using two different electron spectrometers: a CMA in Budapest and DCMA in Warsaw. Prior to measurements, the samples were amorphized by high-energy Ar⁺ ions (100–400 keV), and the surface composition was determined by quantitative XPS. Argon cleaning produces enrichment of samples in the surface layer in Ga (80%) and In (70%), respectively. The experiments refer to a such modified sample surface that was considered in Monte Carlo calculations. The experimental data were analyzed using calibration curves from Monte Carlo calculations which account for multiple elastic scattering events. This approach has been used previously for elemental solids and is now extended to amorphized binary compounds. The experimental values of IMFP obtained in both laboratories exhibited a reasonable agreement with the available literature data in the 0.1–3.0 keV energy range. With respect to the information depth of EPES, the experimental results refer to the bulk composition within a reasonable extent.     

REPRESENTATIONS OF A LOOP LIE ALGEBRA ASSOCIATED WITH QUANTUM PLANE

In this article,some modules over a loop Lie algebra associated to quantum plane are constructed.The isomorphism classes among these modules are also determined.     

Solvable complete lie algebras. I ∗

In this paper, we will discuss the properties of solvable complete Lie algebra, describe the structures of the root spaces of solvable complete Lie algebra, prove that solvable Lie algebras of maximal rank are com-plete, and construct some new complete Lie algebras from Kac-Moody algebras.     

Study on the structural characteristics of HgCdTe photodiodes using laser beam-induced current

The structural characteristics of typical n⁺-on-p HgCdTe photodiodes have been studied by laser beam-induced current (LBIC). The dependence of LBIC on laser wavelength, junction depth and localized leakage has been presented. The diffusion length of minority carrier of p-type region is extracted by the exponential decay fitting of the curve of LBIC. It is found that the peak magnitude of LBIC and junction depth approximate to a linear relationship for practical values of device fabrication. The diffusion length monotonously increases with the junction depth. A notable shift of LBIC profile is observed when localized leakage exists. This provides a useful explain for LBIC applying to characterize the structure and process uniformity of HgCdTe infrared detectors.     

锚定在杂多酸上的席夫碱锰配合物催化磷酸与等摩尔月桂醇绿色酯化反应

 将席夫碱锰配合物与硅钨酸结合制备出一种新颖的无机-有机杂化固体催化剂, 通过红外光谱和热重表征数据推测出这种催化剂的组成和结构, 并将其用于磷酸与等摩尔月桂醇酯化制备长链单烷基磷酸酯 (MAP). 结果表明, 采用 L1-Mn-SiW (L1: 双水杨醛缩-1,6-己二胺) 催化剂, 在优化的反应条件下, 酯化反应可获得 93% 的 MAP 收率和高达 98% 的 MAP 选择性. 催化剂的重复使用测试表明, 液-固多相酯化体系中该固体催化剂可方便地回收, 且具有优异的稳定性, 重复使用 6 次后催化剂活性未见下降, 结构没有变化, 是高效绿色催化剂. 该催化剂作用下的磷酸酯化是固体碱催化过程.     

Crystallization of space: Space-time fractals from fractal arithmetic

Fractals such as the Cantor set can be equipped with intrinsic arithmetic operations (addition, subtraction, multiplication, division) that map the fractal into itself. The arithmetic allows one to define calculus and algebra intrinsic to the fractal in question, and one can formulate classical and quantum physics within the fractal set. In particular, fractals in space-time can be generated by means of homogeneous spaces associated with appropriate Lie groups. The construction is illustrated by explicit examples.     

Electrically controllable unidirectional transmission in a heterostructure composed of a photonic crystal and a deformable liquid droplet

We propose a new method to realize the tunable unidirectional behavior using a heterostructure composed of a one-dimensional photonic crystal and a deformable liquid droplet. We can control the occurrence of the unidirectional behavior in the heterostructure by adjusting the voltage applied on the liquid system. It is demonstrated that when the voltage is not applied most of incident-wave energy can be transmitted through the heterostructure for backward lights. While the forward lights can’t be transmitted, if the voltage is high enough, the one-way behavior disappears. The applied voltage to control the one-way behavior may be relatively low. Thereby, we can expect that the heterostructure may have potential applications in optical devices.     

积分凸性及其应用

该文在Banach空间中通过向量值函数的Bochner积分引进集合与泛函的积分凸性以及集合的积分端点等概念. 文章主要证明有限维凸集、开凸集和闭凸集均是积分凸集，下半连续凸泛函与开凸集上的上半连续凸泛函均是积分凸的, 非空紧集具有积分端点, 对紧凸集来说其积分端点集与端点集一致, 最后给出积分凸性在最优化理论方面的两个应用.     

Modulation of strain,electric field and organic cation rotation on the band gap and electronic structures of organic-inorganic hybrid perovskite CH3NH3PbI3

Band gap modulation engineering is an important step in the application of optoelectronic materials. In this paper, the first-principles calculations were carried out to study the influence of strain, external electric field, spatial orientation of organic cation on the band gaps and electronic structures of organic-inorganic hybrid halide perovskites CH₃NH₃PbI₃. The results show that both the uniform strain and the tetragonal deformation can modulate the band gap obviously. The electric field of 0.2 V/Å is the critical point of the band gap modulation. The band gap increases when an electric field is applied from 0 to 0.2 V/Å. The electric field above 0.2 V/Å will cause the band gap to decrease. The spatial orientation of the organic cation also has modulation influence on the band gap of CH₃NH₃PbI₃, but has no effect on the direct semiconductor characteristics. The above results will be helpful to study the band gap modulation of other organic-inorganic hybrid halide perovskites.