聚酰亚胺薄膜表面微纳米尺度下电荷特性的研究

利用静电力显微镜(electrostatic force microscope,EFM)在微纳米尺度下对聚酰亚胺薄膜表面的电荷起因及特性进行研究.采用Dimension 3100型扫描探针显微镜的导电探针摩擦聚酰亚胺薄膜表面,在薄膜微纳米区域内产生电荷分布.通过静电力显微镜对微纳米区域产生的电荷进行表征,得出探针摩擦速度、探针电压对表面电荷的极性、密度、区域分布有很大的影响.同时也为微纳米尺度下探索聚合物绝缘材料表面电荷生成规律和机理提供了一个新的研究方法和途径.     

扫描静电力显微镜中两种表面结构静电力的自洽计算

扫描静电力显微镜是近年发展起来的一种探测表面微细结构的扫描显微镜．通过带电的原子力显微镜探针与样品之间的静电作用，人们能够获取表面结构的一些信息，如形貌，介电常数等．由于静电力的长程性，扫描静电力显微镜能够弥补扫描隧道显微镜及原子力显微镜探测柔软物体和液体表面结构的不足，因为探针的过近接触会破坏这些表面结构．扫描静电力显微镜已经成功用于水的薄膜凝聚过程的动态信息，铁电晶体畴体以及金属电极等的观测．介观表面结构的静电力信息的探测需要人们对由衬底、样品和探针组成的复杂系统的静电场分布有定量的了解．传…     

微纳米尺度下聚酰亚胺薄膜表面电荷生成规律研究

为进一步研究工业中对聚酰亚胺取向膜基板进行摩擦取向处理时,在取向膜上产生静电残留,影响液晶分子取向的均匀性的问题,文章利用Dimension3100型扫描探针显微镜(SPM)在聚酰亚胺表面摩擦产生了微纳米尺度的电荷,并对表面电荷的生成规律进行了研究。当SPM的导电探针在聚酰亚胺表面进行加工或摩擦操作时,会在探针与薄膜接触区域产生电荷,生成的电荷可以用静电力显微镜(EFM)进行观察。讨论了生成电荷的极性、数量、区域大小与摩擦过程中探针加工速度,所加电压大小、正负之间的关系,为在微观尺度探索聚酰亚胺表面电荷生成规律及生成机理提供了一种新的途径。     

PMMA薄膜nm尺度下表面电荷的制备和观察

利用扫描探针显微镜(SPM)的导电探针在PMMA薄膜表面μm/nm尺度下通过摩擦方式产生了电荷,并用静电力显微镜(EFM)对生成的电荷进行了观察。讨论了生成电荷的极性、数量、区域大小与摩擦过程中探针加工速度、所加电压大小及正负之间的关系:产生电荷的极性与摩擦过程中针尖所加电压的正负保持一致,且所加电压越大,产生电荷的区域和面积越大。但相同情况下,PMMA表面出现的正电荷区域和数量要多于负电荷;针尖带电摩擦时,摩擦速度越快,产生电荷的数量和区域也随之减小。为探索PMMA表面电荷生成规律及生成机理提供了一种新的途径。     

《中国学术期刊文摘》中文版和英文版2007年征订启事

有机光伏打电池可利用更廉价的太阳能，但是需要提高其效率。华盛顿大学的科学家们演示了一种显微技术，能帮助开发者提高有机太阳能电池的效率。这项基于静电力显微镜的新技术揭示了光电薄膜的表面形貌与电池性能的关系。静电力显微镜图像如图1所示。     

基于微石英晶振的动态非接触静电力显微测量(EFM)技术

在一台基于微晶振的原子力显微镜的基础上，通过在针式传感器前端细小针尖加入可调交流偏压，获得高分辨率动态非接触静电力显微镜。此装置可以分别利用微小针尖与样品间的范德华力与附加的可调整电力信号，同时获得样品表面微观形貌特征和表面电特性，如表面电荷分布，表面电势等。     

近场光学显微术进展

讨论了近场光学显微术发展及其理论知识，重点介绍了近场光学显微镜的工作原理、构造设计、工作方式等，概述了近场光学显微术的应用领域和应用成果。探讨了近场光学显微术目前存在的主要问题和需要解决的问题。     

力学参数测量时由残余电荷导致的误差分析

分析了用静电牵引法测量悬臂梁结构力学参数时，由于绝缘层中残余电荷的存在，对测试结果带来的影响；并提出了利用C-V特性曲线确定残余电荷数量的方法，将求出的残余电荷数量从静电力的角度进行等效，从而求出考虑残余电荷后带来的阈值电压测试误差。该分析方法既适于提高悬臂梁、桥等用来测量力学参数的精度，也适于对静电执行器等的精确分析。     

近场光学显微术进展

讨论了近场光学显微术发展及其理论知识,重点介绍了近场光学显微镜的工作原理、构造设计、工作方式等,概述了近场光学显微术的应用领域和应用成果,探讨了近场光学显微术目前存在的主要问题和需要解决的问题。     

纳米测量技术研究现状与发展趋势

详细介绍了纳米测量系统的组成 :纳米传感技术、纳米扫描测试系统、信息处理与图像分析技术 ;综述了纳米测量技术国内外现状 ;在此基础上 ,提出了纳米测量需解决的关键技术及今后的发展方向。     

电场力显微镜不同探针对表面电荷注入的影响

在电场力显微镜(EFM)下利用不同金属镀层微探针,在微纳米尺度下对聚酰亚胺薄膜的表面电荷生成特性进行研究。采用电场力显微镜导电探针在聚酰亚胺薄膜表面注入电荷,并对微纳米区域产生的电荷进行表征,结果表明不同金属镀层的微探针对聚酰亚胺薄膜上电荷注入效果不同。铂铱合金镀层具有比钴铬合金镀层更高的功函数fm,因此前者在金属-电介质接触中产生更大肖特基势垒,进而降低了电荷的注入程度。该研究为微纳米尺度下探索聚合物绝缘材料表面电荷生成、发展机理提供了一个新的研究方法和途径。     

Charge carrier mobility,bimolecular recombination and trapping in polycarbazole copolymer:fullerene (PCDTBT:PCBM) bulk heterojunction solar cells

Organic photovoltaic devices based on the donor:acceptor blend of poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl C₆₁ butyric acid methyl ester (PCBM) have received considerable attention in recent years due to their high power conversion efficiencies and the ability to achieve close to 100% internal quantum efficiency. However, the highest efficiencies were all attained using active layers of less than 100 nm, which is not ideal for either maximised potential performance or commercial viability. Furthermore, more recent reports have documented significant charge carrier trapping in these devices. In this paper two charge extraction techniques (photo-CELIV and time-of-flight) have been used to investigate the mobility and recombination behaviour in a series of PCDTBT:PCBM devices. The results not only confirm significant charge carrier trapping in this system, but also reveal close to Langevin-type bimolecular recombination. The Langevin recombination causes a short charge carrier lifetime that results in a short drift length. The combination of these two characteristics (trapping and fast bimolecular recombination) has a detrimental effect on the charge extraction efficiency when active layers greater than ∼100 nm are used. This accounts for the pronounced decrease in fill factor with increasing active layer thickness that is typically observed in PCDTBT:PCBM devices.     

Temperature dependence of turn-on voltage of gold-doped MOSFETs

The temperature dependence of the turn-on voltage of gold-doped and control n- and p-channel MOSFETs has been measured. To account for the large positive shift of turn-on voltage, VT Au, of gold treated n- and p-channel devices, it has been proposed that the gold eliminates the fast interface traps of continuous energy distribution, and that additional acceptor states very close to the valence band can cause additional charge QA Au, which can dominate the effect of acceptor and donor levels of gold ions in the silicon surface space charge region, and can also over-compensate the surface state charge, Qss. To fit the theoretical VT Auversus T curve to experimental curves, an accumulation of electrically active gold within the surface space charge region has been considered in n-channel devices and depletion in p-channel devices.     

用于DVD伺服控制的EFM/EFM+解调器的设计

本文介绍了一种EFM/EFM+解调器的设计和实现.该解调器用于DVD光盘伺服控制,对读入的CD和DVD数据分别实现14-8和16-8解调.文中通过对其工作原理和实际应用的分析,给出其最终实现方案.并用Verilog硬件描述语言完成整个解调器的设计工作.功能仿真和FPGA验证表明,设计成功.     

Computer model and charge transport studies in short gate charge-coupled devices

A computer model has been developed that simulates charge transport of carriers in a surface channel charge-coupled device. This model is based on the charge continuity and current transport equations with a time dependent surface field. The device structure of the model includes a source diffusion an input gate and transfer gate. The present model is the first real simulation of the input scheme of the surface-channel CCDs. The scooping and spilling techniques associated with the charge injection process are simulated by the input diffusion which is included in the model.As an application to a CCD practical problem the present model has been used to study the linearity of the electrical charge injection into surface channel charge-coupled devices. The generated harmonic components of a sinusoidal input are calculated using the transfer characteristics of the input stage obtained from the computer simulation.Using this model the spatial variations of the self-induced fringing field and total currents under the storage and transfer gates were computed. The charge transfer mechanisms for short-gate (L ≤ 8 μm) CCDs was investigated. It was found that for short gates the charge transfer efficiency is governed mainly by the fringing field and self-induced current mechanisms. The results of this study help to clarify the mechanism by which the signal-charge level and gate length affect the charge transfer efficiency.     

Oxide charge measurements in EEPROM devices

A method to measure “on site” programmed charges in EEPROM devices is presented. Electrical AFM based techniques (Electric Force Microscopy (EFM) and Scanning Kelvin Probe Microscopy (SKPM)) are used to probe directly floating gate potentials. Both preparation and probing methods are discussed. Sample preparation to access floating gate/oxide interfaces at a few nanometers distance without discharging the data reveals to be the key point, more than the probing technique itself.     

The Relationship between Chemical Flexibility and Nanoscale Charge Collection in Hybrid Halide Perovskites

Hybrid organometal halide perovskites are known for their excellent optoelectronic functionality as well as their wide‐ranging chemical flexibility. The composition of hybrid perovskite devices has trended toward increasing complexity as fine‐tuned properties are pursued, including multielement mixing on the constituents A and B and halide sites. However, this tunability presents potential challenges for charge extraction in functional devices. Poor consistency and repeatability between devices may arise due to variations in composition and microstructure. Within a single device, spatial heterogeneity in composition and phase segregation may limit the device from achieving its performance potential. This review details how the nanoscale elemental distribution and charge collection in hybrid perovskite materials evolve as chemical complexity increases, highlighting recent results using nondestructive operando synchrotron‐based X‐ray nanoprobe techniques. The results reveal a strong link between local chemistry and charge collection that must be controlled to develop robust, high‐performance hybrid perovskite materials for optoelectronic devices.     

射频离子辐射损伤的激光退火

本文介绍了等离子刻蚀和去胶对MOS、MNOS电容器和双板晶体管所产生的辐射损伤的激光退火，用连续CO2激光器从背面照射蕊片，可以明显地降低各种MIS结构中的固定电荷和界面陷阱，完全消除辐射损伤，使被损伤的器件特性得到恢复并有所改善，使集成电路成品率明显提高。     

Experimental confirmation of an analytical model for charge transfer in charge-coupled devices

An analytical model for the charge loss as a function of transfer time under low charge levels in surface channel charge-coupled devices has been theoretically determined and experimentally confirmed. The model includes the effect of surface states. A new method of measuring charge transfer makes it possible to determine the role that surface states play in the degradation of signal charge transfer.     

The study of the charge collection of the normal‐collector configuration

Charge collection is one of the crucial processes to collect the induced current when a semiconductor sample is subjected to some external excitations such as the electron or photon beams. The charge collection probability is the basis in the study of this induced current particularly in the field of photonic devices, photovoltaic cells as well as in the characterization of semiconductor materials and devices. In this paper, the analytical expressions for the charge collection probability of the finite‐dimension normal‐collector configuration, with and without surface recombination at the free surfaces are presented. An excellent agreement has been found between the charge collection probability profiles computed using the presently derived analytical expressions and those obtained using a device simulator. The results have been used to study the effects of the various physical parameters on the charge collection probability. These analytical expressions are expected to enhance our understanding of the charge collection process. Copyright © 2012 John Wiley & Sons, Ltd.