Study of thermally-induced effects on Si–Ge amorphous layers using optical measurements

Thin films of elemental Si and Ge were grown one after another onto glass substrate using electron beam evaporation method. Optical measurements were used to probe the thermally-induced effects on Si–Ge layers upon annealing at 100 °C. Thermal treatment of the films was carried out under vacuum, to avoid oxidation of the films, at a temperature of 100 °C. X-ray diffraction, XRD, showed that the as-deposited layers are amorphous. The change of some optical parameters such as transmission and optical energy gap, as a result of the heat treatment, was explored. The optical energy gap as well as the optical transmission of the dual layer sample was found to increase with annealing time. The obtained results show the possibility of tailoring the layer structure to meet certain technological applications in terms of optical transmission and optical energy gap. Scanning Electron Microscope, SEM, was used to study the morphology of the as-deposited and annealed films. As-deposited films showed no crystalline features. However, the annealed films show some partial crystallization that increases with annealing time. The observed structural changes result in an increase of the optical energy gap with annealing.     

真空炉温度模糊PID复合控制

在详细介绍真空退火炉温控系统设计的基础上,讨论双闭环FUZZY PID复合温度控制原理。     

Role of oxygen in enhancing N-type conductivity of CuInS2 thin films

Post-growth treatments in air atmosphere were performed on CuInS₂ films prepared by the single-source thermal evaporation method. Their effect on the structural, optical and electrical properties of the films was studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), optical reflection and transmission and resistance measurements. The films were annealed from 100 to 350 °C in air. The stability of the observed N-type conductivity after annealing depends strongly on the annealing temperature. Indeed it is shown that for annealing temperatures above 200 °C the N-type conductivity is stable. The resistance of the N-CuInS₂ thin films correlates well with the corresponding annealing temperature. The samples after annealing have direct bandgap energies of 1.45-1.50 eV.     

Diamond nanocrystals and amorphous SiOx nanowires formed by rapid thermal annealing of carbon film

Rapid thermal annealing (RTA) has been performed on the carbon films prepared by radio frequency plasma-enhanced chemical vapor deposition on Si substrate. The RTA at 800 °C for 60 s leads to the formation of many diamond nanocrystallites agglomerating on the film surface. Higher temperature RTA at 1100 °C for 60 s induces the high-density amorphous SiO_x (x = 1.2) nanowires on the film surface without diamond nanocrystallites. At both the RTA temperatures, a well-oriented SiC interlayer is also formed simultaneously. The sp³ sites in the carbon film and the oxygen during the RTA treatment as well as the RTA temperature are considered to play important roles in determining the final reaction products.     

Hydrostatic pressure effect on dislocation evolution in self-implanted Si investigated by electron microscopy methods

The influence of enhanced hydrostatic pressure on evolution of dislocations in self-implanted silicon during annealing at different temperatures was investigated by means of electron microscopy methods. It is found that the main cause of the pressure impact differs for various annealing temperatures. The annealing under enhanced pressure at lower temperature (1070 K) has a negligible effect on structure of dislocations located in a thin layer (end-of-range (EOR) defects). At this temperature, enhanced pressure mainly increases the density of microdefects with oxygen precipitation. It is found that after high-temperature annealing (1400 K), enhanced hydrostatic pressure (HP) reduces dislocation density near the surface; however, dislocations extend deeper into the substrate as compared to the samples annealed under atmospheric pressure. The effect is attributed mainly to the reduction of silicon interstitial-atoms migration towards the surface due to increase in energy necessary to make silicon interstitial atom occupy a lattice site at the surface.     

Polycrystalline growth and recrystallization processes in sputtered ITO thin films

Indium tin oxide (ITO) thin films with various thicknesses from 170 to 700 nm have been grown onto unheated glass substrates by sputtering from ceramic target, and subsequently annealed in vacuum at temperatures ranging from 250 to 350 °C. The structure, morphology and electro-optical characteristics of the ITO samples have been analyzed by X-ray diffraction, atomic force microscopy, four-point electrical measurements and spectrophotometry. Polycrystalline ITO growth has been found varying with film thickness. The thickness also determined the recrystallization achievable by annealing and the electro-optical thin film properties.     

混合遗传算法与模拟退火法

论文将适合全局搜索的遗传算法(GA)和适合局部搜索的模拟退火算法(SA)相结合,提出了混合GA-SA计算方法。一方面,算法采用混沌初始化,提高了初始群体的质量;另一方面,算法采用Gray编码以及动态自适应调节交叉概率和变异概率,提高了收敛速度,并有效防止种群早熟现象。实例验证了该算法的可行性和有效性。     

基于曲率图小波分解的平面曲线光顺方法*

将模拟退火遗传算法用于聚类分析，通过对聚类中心进行编码，定义适应度函数，选择、交叉、变异操作以及模拟退火算法的运用，给出了一种新的基于模拟退火遗传算法的聚类算法，实验结果显示该方法优于基本的遗传算法。     

Real-time studies during coating and post-deposition annealing in organic semiconductors

In this contribution we explore the use of real time spectroscopic probes to gain useful insights into the kinetics of semiconductor polymer chains during thin film formation and upon post-deposition annealing treatments. In-situ ellipsometry is employed to monitor the deposition of thin films of the workhorse material system for organic photovoltaics (soluble derivative fullerene blended with poly(3-hexylthiophene)), when processed from solution using an analogous dip coating deposition method. This allows for detailed time investigation of the dynamics of film formation. Moreover, we applied spectroscopic photometry to study the in-situ crystallization and diffusion of polymer chains during post-deposition solvent annealing.     

Near-interface doping by ion implantation in Cu(In,Ga)Se2 solar cells

Cu(In,Ga)Se₂ absorber layers were implanted with 20 keV Cd ions in order to investigate the influence of changes in the near-interface doping profile. Modifications in this region are shown by AMPS-1D simulations to have substantial impact on solar cell properties. Ion implantation and subsequent thermal annealing steps were monitored by SIMS measurements to control the thermal diffusion of the dopant. Solar cells both with and without CdS buffer layer were made from the implanted absorbers and characterized by j-V and EQE measurements. These experimental results in conjunction with simulations of the quantum efficiency show that a well-defined type-inversion of the implanted layer can be achieved by low-energy ion implantation.