Improving Ideality of P-Type Organic Field-Effect Transistors via Preventing Undesired Minority Carrier Injection

Electron injection plays a crucial role in arousing the double-slope characteristics for p-type organic field-effect transistors (OFETs) with narrow-bandgap organic semiconductors (OSCs). This issue will not only result in the misrepresentation of OFET performance but also may cause device instability, hence impeding their further development in real-world applications. A facile and highly efficient approach is developed to circumvent this issue by implementing modification on the electrode/organic semiconductor interface. An ultrathin layer of wide-bandgap OSC with suitable energy levels is introduced to block the undesirable electron injection. By this means, typical double-slope behaviors and bias stress stability in the p-type OFETs can be significantly improved. Using 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene-based OFETs the double-slope behaviors of as-fabricated devices are effectively converted to near-ideal behaviors after modification, leading to a dramatic improvement of average reliability from 65.11% to 91.76%. Furthermore, the positive drift of transfer curves under prolonged bias stress is also successfully suppressed. This strategy demonstrates good universality and can provide a new guideline for the fabrication of OFETs with ideal behaviors.     

旅游驱动的少数民族建筑景观变迁研究——以九寨沟为例

旅游发展驱动的少数民族建筑景观的变迁,是旅游对区域文化影响的重要表现.文章通过对九寨沟树正寨的实地问卷与深入访谈调查,分析了居民和游客对藏寨建筑景观特色变迁的感知,认为居民对藏寨建筑景观的特色并没有清晰的认识,保护没有得到重视,而游客也缺乏对真实藏族传统文化的认识.研究认为,少数民族旅游地传统民族文化的保护,重在认清民族文化的差异和精华,增强当地居民的自我认同,促进社区居民参与旅游规划和管理,培养主人意识,形成对民族文化保护和传承的自觉性;同时还需要深化旅游地的管理,以引导为主,积极应对经济水平提高以后居民对生活环境改造的合理要求.     

土家族吊脚楼的建造特点——以鄂西彭家寨古建测绘为例

以鄂西彭家寨的吊脚楼群为例,在建筑实地测绘基础上,从建筑选址、空间布局、建造技术、文化传承等角度对土家族吊脚楼这一独特而优美的传统建筑形式进行描述.     

少数民族地区特色旅游规划及设施建设研究--以江华瑶族自治县旅游发展规划研究为例

在现代化建设日新月异的今天，针对少数民族地区做好旅游发展规划，如何加强营造城市特色，突出特质景观，保护其丰富而有内涵的人文自然环境，以风貌特色吸引游人，促进地方旅游和经济发展。     

传热过程对多晶硅真空定向凝固过程的凝固界面及热应力的影响

以实验室10 t/a VODS型多晶炉为原型,对其凝固过程的热场、固液界面和热应力进行了瞬态模拟与实验验证。结果表明:在坩埚底部有水冷热交换块的真空定向凝固系统中硅料凝固会产生较大的热应力,增加环形保温结构使热区封闭后可改变炉内换热过程,从而改变硅料凝固情况;硅料在坩埚底部为石墨热交换块的系统中凝固时产生的热应力相对较小,但固液界面的形状会发生较大的改变,影响晶粒的生长。炉膛内径适当变宽有利于炉内热区温度分布更合理,使得硅料凝固时的固液界面更加理想。通过实验验证了多晶硅在坩埚底部无需进行水冷换热情况下进行真空定向凝固能达到冶金法生产太阳能级多晶硅的要求,这为提高冶金法制备太阳能级多晶硅质量、降低系统能耗具有一定的指导意义。     

Evolution of silicon bulk lifetime during III–V‐on‐Si multijunction solar cell epitaxial growth

The evolution of Si bulk minority carrier lifetime during the heteroepitaxial growth of III–V on Si multijunction solar cell structures via metal‐organic chemical vapor deposition (MOCVD) has been analyzed. In particular, the impact on Si lifetime resulting from the four distinct phases within the overall MOCVD‐based III–V/Si growth process were studied: (1) the Si homoepitaxial emitter/cap layer; (2) GaP heteroepitaxial nucleation; (3) bulk GaP film growth; and (4) thick GaAs_yP_1‐y compositionally graded metamorphic buffer growth. During Phase 1 (Si homoepitaxy), an approximately two order of magnitude reduction in the Si minority carrier lifetime was observed, from about 450 to ≤1 µs. However, following the GaP nucleation (Phase 2) and thicker film (Phase 3) growths, the lifetime was found to increase by about an order of magnitude. The thick GaAs_yP_1‐y graded buffer was then found to provide further recovery back to around the initial starting value. The most likely general mechanism behind the observed lifetime evolution is as follows: lifetime degradation during Si homoepitaxy because of the formation of thermally induced defects within the Si bulk, with subsequent lifetime recovery due to passivation by fast‐diffusing atomic hydrogen coming from precursor pyrolysis, especially the group‐V hydrides (PH₃, AsH₃), during the III–V growth. These results indicate that the MOCVD growth methodology used to create these target III–V/Si solar cell structures has a substantial and dynamic impact on the minority carrier lifetime within the Si substrate. Copyright © 2015 John Wiley & Sons, Ltd.     

受主型杂质对p型单晶硅中少子衰减过程的影响

少子寿命测试技术是监控单晶硅中杂质和缺陷的数量及性质的重要技术手段.基于常规光电导少子寿命测试的基本参数,研究了不同性质的受主型杂质缺陷对太阳电池用p型单晶硅中少子衰减过程的影响,并重点分析了仅存在受主型电子陷阱或复合中心时,少子衰减过程的变化规律;受主型电子陷阱和复合中心并存时,少子衰减过程的变化规律.研究表明:p型单晶硅中仅存在电子陷阱或复合中心时,二者的密度和俘获截面越小,少子寿命越长,且二者均存在一个最小阈值;当二者并存时,少子电子的衰减过程可根据少子寿命值的不同分成不同的衰减区域.     

An objective and interactive-information-based feedback mechanism for the consensus-reaching process considering a non-support degree for minority opinions

The consensus-reaching process (CRP) to achieve higher unanimity and ensure common agreement before deriving a final decision has become an important procedure in group decision-making problems. The demand for high-quality decision results has motivated the development of large-scale group decision-making (LGDM). In such cases, the issue of minority opinion has gained awareness due to the related effects on enhancing consensus and decision quality. A minority opinion cannot exert an effect unless the majority attach importance to whether that opinion is supported or not. To reflect the effect of minority opinions on consensus, this paper establishes a LGDM framework with an objective and interactive-information-based feedback mechanism for the CRP. Given the natural forms of human expression, multi-granular linguistic information and a 2-tuple linguistic model are used. First, initial weights are objectively assigned to decision-makers (DMs) to weaken the impact of the majority. Subsequently, a non-support degree function is newly defined to reflect the extent to which other DMs dissent from a minority opinion. More importantly, feedback rules are constructed to make corresponding adjustments to the powers of discourse among all DMs in the attempt to reach consensus. Finally, the proposed three-phase LGDM framework is applied to new product development (NPD), and simulation experiments are conducted based on two algorithms to verify the framework's applicability and feasibility.     

电子辐照GaInP/GaAs/Ge三结太阳电池少子寿命的变化

为研究电子辐照空间太阳电池的损伤机制，对电子辐照GaInP/GaAs/Ge三结太阳电池进行了光致发光谱测量，分析了GaInP顶电池及GaAs中间电池发光强度随电子注量的变化规律。利用辐射效率关系对归一化发光强度随电子辐照注量的变化进行了拟合，分别得到了GaInP顶电池及GaAs中间电池在不同辐照条件下的少子非辐射复合寿命τ_nr，通过对比辐照前后少子非辐射复合寿命的衰降变化，发现GaInP顶电池的抗辐照性能优于GaAs中间电池。     

贵州民族建筑现代境遇

从少数民族传统建筑建造过程的现状反思如何对待少数民族传统建筑的保护,发展和继承问题。