InP表面等离子体CVD淀积SiO2膜的界面结构及C—V特性

报道了以正硅酸乙酯（ＴＥＯＳ）为源，采用等离子体增强化学汽相淀积（ＰＥＣＶＤ）技术在ＩｎＰ表面低温生长ＳｉＯ２钝化膜。对ＳｉＯ２／ＩｎＰ界面态进行了Ｘ射线光谱（ＸＰＳ）分析和Ｃ－Ｖ特性研究。     

聚合物墙表面组成的调控及其对聚合物墙液晶器件光电性能的影响

本文探究了单体与液晶的相容性对聚合物墙表面组成的影响和表面组成对聚合物墙液晶器件光电性能的影响及其调控方法。选取与液晶相容性相差较大但表面能相近的单体,通过表面引发聚合形成与液晶分层的聚合物薄膜,洗去液晶后用反应离子刻蚀在聚合物表面刻蚀出不同深度。通过衰减全反射红外光谱和X射线光电子能谱仪表征不同深度的组分。最后利用掩模版制备聚合物墙液晶器件,并探究聚合墙表面组成对其光电性能的影响。实验结果表明：在聚合物-液晶界面处富集与液晶相容性高的聚合物组分,并且聚合光强越低,这种组分偏析效果越明显,当聚合光强较低时,聚合物表面组成中的PTFEMA组分占比为68.5%,比高光强时的多出10.6%。聚合物墙的表面组成对液晶器件的光电性能有一定的影响,当光强为10mW/cm²时器件的阈值电压为0.879V,而在70mW/cm²光强时升高到1.172V。可以利用单体与液晶的相容性差异以及光强调控聚合物墙表面组成,进而影响液晶器件的光电性能。     

表面活性剂对聚合物分散液晶光电性能的影响

为了调控聚合物分散液晶(PDLC)中聚合物基体和液晶微滴的界面作用,降低锚定能,以聚丙烯酸甲酯(PMA)为基体,E7为分散相,并加入了不同含量的硬脂酸(SA)表面活性剂,采用聚合物诱导相分离法制备了PDLC,并对PDLC的光电性能进行了测试。研究发现,PDLC的电光性能随着SA含量的增加而改善,但当SA的含量达到一定值后,液晶微滴出现\"岛聚\"现象,光电曲线出现一个转折点。实验结果表明,表面活性剂可以调控聚合物和液晶微滴的界面作用,降低锚定能,从而改善PDLC的光电性能。

     

Au/Zn/Au/p-In P欧姆接触的界面研究

研究了离子束溅射制备的Au/Zn/Au/p-InP欧姆接触的界面特性.在480℃退火15s比接触电阻达到最小,为1.4×1 0-5 Ω·cm 2.利用俄歇电子能谱(AES)和X射线光电子能谱(XPS)研究了接触界面的冶金性质.实验结果表明,在室温下InP中的In就可以扩散到接触的表面,退火后可与Au形成合金.退火后,Zn的扩散可以在p-InP表面形成重掺杂层,从而降低接触势垒高度,减小势垒宽度,有助于欧姆接触的形成;在接触与p-InP的界面产生一个P聚集区,同时Au与InP反应生成Au2P3,其P的2p3/2电子的结合能约为129.2 eV.     

低维半导体/钙钛矿异质结构光电探测器的研究进展

光电探测器能将光辐照转换为电信号,是光电系统中接收端的核心部件,在国民经济、警用装备以及诸多军事领域都有着重要的应用。基于传统材料的光电探测器面临性能不够优越、单个探测器检测范围窄等问题。近年来,低维半导体和钙钛矿材料在光电探测器领域引起研究人员的广泛关注。相较单一材料,基于低维半导体/钙钛矿异质结构的光电探测器在光响应度、外量子效率、探测率以及响应时间上都有着更为优越的性能,逐渐成为研究热点。简述了光电探测器的基本性质以及钙钛矿材料常见的制备方法,进一步介绍了国内外关于低维半导体/钙钛矿异质结构光电探测器的主要研究进展,探讨了目前优化性能的主要措施,最后对发展前景进行了展望,并提出了相关建议。     

聚合物半导体聚乙炔的热激电流谱研究

本文首次给出聚合物半导体材料聚乙炔(CH)_x的热激电流(TSC)谱,观察到聚乙炔的异构化现象,并获得关于聚乙炔极化现象的新结果。本文还给出按照理论公式由实验测得的热激电流峰曲线求得相应激活能的计算机拟合程序     

二维界面修饰对全无机CsPbBr3薄膜光电性能的调控

全无机CsPbBr₃钙钛矿太阳能电池中的电荷传输层与钙钛矿层界面的载流子复合是制约其光电转换效率进一步提升的关键因素。文中采用带隙和带边可调控的二维过渡金属硫族化合物（MoS₂、MoSe₂、WS₂和WSe₂）材料作为电子传输层和钙钛矿层之间的界面修饰材料和载流子传输材料,利用晶格匹配的范德华外延生长高质量的钙钛矿薄膜,同时通过界面能级补偿和势垒消减,降低钙钛矿层与电子传输层之间的界面电荷损失,促进全无机CsPbBr₃钙钛矿太阳能电池器件中载流子的提取与传输,使器件光电转换效率由初始的7.94%提高到10.02%,同时开路电压从1.474 V提升至1.567 V。该研究为制备高质量的钙钛矿薄膜同时实现界面能级匹配的高性能光电器件提供了一条新途径。     

负性液晶材料光电参数对聚合物稳定液晶器件响应特性的影响

当前聚合物稳定液晶器件的光电响应特性尚未完全满足智能窗的实用需求。材料的自身特性是决定液晶器件性能的关键,因此本文重点研究了负性液晶材料的介电各向异性和双折射率两项核心参数对聚合物稳定液晶器件光电响应特性的影响趋势,并给出对应的最佳参数。本文采用实验和仿真相结合的研究方法,首先选用具有不同参数的负性液晶材料制备聚合物稳定液晶器件,研究分析介电各向异性对器件光电性能的影响。然后通过仿真模拟,研究负性液晶材料的双折射率对器件光电效应的影响。最后通过实验和仿真结果的综合分析得出最佳负性液晶参数。研究结果表明,介电各向异性越大,液晶分子越容易被电场驱动,液晶器件的光电性能也就越好。在固定聚合物稳定网络双折射率的情况下,当负性液晶的双折射参数为n_e=1.49、n_o=1.593时,可达到最优雾度。这一研究结果可为聚合物稳定液晶器件性能的优化及产业化的发展提供理论指导。     

不同单体配比对聚合物网络及聚合物稳定胆甾相液晶器件光电性能的影响

为了调节聚合物网络与液晶分子之间的相互作用,从而改善聚合物稳定胆甾相液晶（PSCLC）的光电性能,本文采用紫外光聚合诱导相分离法（PIPS）制备了聚合物稳定胆甾相液晶,通过控制2种单体RM257与BAB6的比例来改善器件性能。随着RM257含量的减少,聚合物网络由取向排列的纤维状结构向疏松不规整的交联状结构转变,形成的聚合物网络对液晶分子的锚定作用减弱,聚合物稳定胆甾相液晶的饱和电压降低,关闭时间增大。当RM257与BAB6质量比为1：4时,聚合物稳定胆甾相液晶器件具有较好的对比度。     

有机层／阴极界面修饰对体异质结聚合物太阳能电池性能的影响

通过制备四种不同结构的器件,详细分析研究了活性层／阴极界面修饰对P3HT:PCBM聚合物体异质结太阳能电池性能的影响。当在P3HT:PCBM薄膜上旋涂一层PCBM,并蒸镀0.5 nm LiF时所制备的器件的填充因子和光电转换效率都得到较大的提高。对器件的光电性能和薄膜的形貌进行深入分析,阐明界面修饰的作用机理。     

Simple source/drain contact structure for solution-processed n-channel fullerene thin-film transistors

This paper describes a simple approach for reducing the contact resistances at the source/drain (S/D) contacts in solution-processed n-channel organic thin-film transistors (OTFTs). Blending poly(ethylene glycol) (PEG) into the fullerene semiconducting layer significantly improved the device performance. The PEG molecules in the blends underwent chemical reactions with the Al atoms of the electrodes, thereby forming a better organic-metal interface. Further, the rougher surface obtained after the addition of PEG could also increase the effective contact area, thereby reducing the resistance. As a result, the electrical properties of the devices were significantly improved. Unlike conventional bilayer structures, this approach allows the ready preparation of OTFTs with a low electron injection barrier at the S/D contacts.     

A diketopyrrolopyrrole-based regular terpolymer bearing two different π-extended donor units and its application in solar cells

In this study, to adjust the desired molecular energy levels and bandgap energies of polymers for photovoltaic applications, a regular terpolymer structure was designed. A new regular terpolymer, poly(DPP4T-alt-TBP), containing diketopyrrolopyrrole (DPP), BT, and BP units in the repeating group was successfully synthesized. The DPP-BT monomeric unit in polymer backbone enhanced chain packing and induced a high-lying highest occupied molecular orbital (HOMO) level and the DPP-BP segment induced a deeper HOMO level. The lowest unoccupied molecular orbital (LUMO) level of the terpolymer was also controlled in a similar manner. The HOMO level of the terpolymer was similar to that of poly(DPP-alt-BP), and the energies of the LUMOs were governed by the DPP-BT unit. The polymer chain arrangement of the terpolymer on the substrate was observed to be a mix of face-on and edge-on orientations, which is a different chain arrangement mode to those shown in both poly(DPP-alt-BP) and poly(DPP-alt-BT). A TFT fabricated with poly(DPP4T-alt-TBP) had a charge carrier mobility of 0.59 cm² V⁻¹ s⁻¹ and a moderately high current on/off ratio. Furthermore, a polymer solar cell containing the terpolymer and PC₇₁BM had a power conversion efficiency of 4.54%, which is significantly higher than those of the PCEs of poly(DPP-alt-BP) and poly(DPP-alt-BT)-based solar cells with identical device configurations.     

Ⅲ-Ⅴ族化合物低维半导体材料制备技术及进展

低维半导体材料特别是Ⅲ -Ⅴ族化合物低维半导体材料日益受到人们的重视和深入的研究。文章回顾和评述了近几年Ⅲ -Ⅴ族化合物低维半导体材料包括量子阱、量子线、量子点的制备技术的进展 ,展望了这些技术在光电子器件等方面的应用前景。     

光声室低频特性的研究

本文采用气体光声室检测方法,研究了在较低的斩波频率(低于500Hz)下,半导体材料硅、锗、砷化镓和碲化镉的光声频率特性,得出了改进的高灵敏度光声室光声信号的理论表达式,给出了R-G理论的修正项,其理论计算和实验结果符合得较好。     

Interface electronic structure between organic semiconductor film and electrode metal probed by photoelectron yield spectroscopy

We present an investigation of the interface between organic semiconductor films and metal substrates (organic/metal interface) using photoelectron yield spectroscopy (PYS) as the probing technique. PYS studies were conducted on the pentacene/Au, copper phthalocyanine (CuPc)/Au, and perfluorinated zinc phthalocyanine (F₁₆ZnPc)/Au, and the results were compared with literature results obtained using conventional ultraviolet photoemission spectroscopy (UPS). PYS is advantageous for probing the electronic structure of the organic/metal interface because of the relatively long mean free path of photoexcited electrons with very low kinetic energy in PYS, which enables the detection of the photoelectrons from the metal substrate buried deep in the organic film. We demonstrate herein that the use of PYS reduces the significance of the final state effect of the electronic density surrounding the photohole at the organic molecule generated after the photoemission; this effect is known as the electric polarization effect. Although this effect has a significant influence on the results obtained using conventional UPS, the reduced influence of the final state effect in PYS makes it possible to construct an energy level diagram at the organic/metal interface with greater accuracy than can be achieved with UPS. In addition, a novel mechanism of the photoelectron detection for PYS enables us to apply PYS to very thick organic films, and therefore, PYS provides a reliable value of ionization energy for organic films without the influence of the substrate.Because the interface electronic structure has a significant influence on the carrier injection properties of organic devices, the increased reliability of the information obtained by PYS will render it very useful for the improvement of device performance as well for understanding their operation principles.     

微加工获得的F-P半导体激光器的光谱特性分析

利用微加工法可以在FP半导体激光器中引入具有反射功能的缺欠点或面来改进激光器的光谱特性。作者导出了含有多个缺欠点的微加工获得的FP半导体激光器(MMLD)的输出谱表达式,并对MMLD振荡模的边模被抑制的情况作了简要的说明。     

Origin of electron mobility enhancement in (1 1 1)-oriented InGaAs channel metal-insulator-semiconductor field-effect-transistors

Electrical and physical characteristics of the Al₂O₃/InGaAs interfaces with (1 1 1)A and (1 0 0) orientations were investigated in an attempt to understand the origin of electron mobility enhancement in the (1 1 1)A-channel metal-insulator-semiconductor field-effect-transistor. The (1 1 1)A interface has less As atoms of high oxidation states as probed by X-ray photoelectron spectroscopy. The electrical measurements showed that energy distribution of the interface traps for the (1 1 1)A interface is shifted toward the conduction band as compared to that for the (1 0 0) interface. Laterally-compressed cross-section transmission electron microscopy images showed that the characteristic lengths of the interface roughness are different between the (1 1 1)A and (1 0 0) interfaces. The contributions of the Coulomb and roughness scattering mechanisms are discussed based on the experimental results.