过渡区p型氢化硅氧薄膜结构和光电特性的研究

采用射频等离子体增强化学气相沉积技术,利用二氧化碳(CO_2)、氢气(H_2)、硅烷(SiH_4)和乙硼烷(B_2H_6)作为气源,制备出一系列p型氢化硅氧薄膜.利用拉曼光谱、傅里叶变换红外光谱和暗电导测试,研究了不同二氧化碳流量对薄膜材料结构和光电特性的影响,获得了从纳米晶相向非晶相转变的过渡区P层.研究表明:随着二氧化碳流量从0增加到1.2 cm~3·min~(-1),拉曼光谱的峰值位置从520 cm~(-1)逐渐移至480 cm~(-1).材料红外光谱表明,随着二氧化碳流量的增加,薄膜中的氧含量逐渐增加,氢键配置逐渐由硅单氢键转换为硅双氢键.P层SiO:H薄膜电导率从3S/cm降为8.3×10~(-6)S/cm.所有p型SiO:H薄膜的光学带隙(Eopt)都在1.82—2.13 eV之间变化.在不加背反射电极的条件下,利用从纳米晶相向非晶相转变的过渡区P层作为电池的窗口层,且在P层和I层之间插入一定厚度的缓冲层,制备出效率为8.27%的非晶硅薄膜电池.     

倾斜式生长ZnS纳米柱状薄膜及其透射性能的研究

采用倾斜式生长的方法,在本底真空为3×10-4 Pa,生长率为0.2 nm·s-1的条件下,通过改变衬底的法线方向与入射粒子流的夹角α,在ITO导电玻璃衬底上制备了ZnS纳米薄膜。在α=80°和85°时,样品的Ｘ射线衍射谱证实了不同倾斜角时所制备薄膜中均有纳米ZnS晶体形成,扫描电子显微镜(SEM)图像显示,所形成的薄膜均呈现出了柱状结构,并且倾斜角为85°时所得到的纳米柱直径大于80°时所得结果;在α=0°时,相应测量结果表明,虽然在不同衬底上也形成了纳米ZnS晶体薄膜,但并未见柱状结构,而是形成了一层均匀且致密的薄膜。对两种薄膜结构的生长动力学过程作了分析。ITO衬底上薄膜的透射光谱表明ZnS柱状薄膜能够提高可见光的透过率,因此对柱状ZnS纳米薄膜的研究将有利于提高电致发光器件的发光效率。     

Thickness dependence of surface morphology and charge carrier mobility in organic field-effect transistors

With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and charge carrier mobility in pentacene and regioregular poly (3-hexylthiophene) (RR-P3HT) field-effect transistors. On the basis of the results of surface morphologies and electrical properties, we presume that the charge carrier mobility is largely related to the morphology of the organic active layer. We observe that the change trends of the surface morphologies (average size and average roughness) of pentacene and RR-P3HT thin films are mutually opposite, as the thickness of the organic layer increases. Further, we demonstrate that the change trends of the field-effect mobilities of pentacene and RR-P3HT FETs are also opposite to each other, as the thickness of the organic layer increases within its limit.     

CdSe/CdMnSe多量子阱的激子光学性质的研究

用分子束外延在GaAs衬底上生长了CdSe/CdMnSe多量子阱结构.利用X射线衍射(XRD)、变密度激发的PL光谱、变温度PL光谱和变密度激发的ps时间分辨光谱研究了CdSe/CdMnSe多量子阱结构和激子复合特性.讨论了随温度升高辐射线宽展宽和辐射复合效率降低的机理.发现不同激发密度下发光衰减时间不同,认为它的机理可能是无辐射复合引起的.在该材料中观测到激子激子散射发射峰,它被变密度激发和变温度PL光谱所证实. 关键词： CdSe/CdMnSe 量子阱 光学性质     

Vacuum relaxation and annealing-induced enhancement of mobility of regioregular poly（3-hexylthiophene） field-effect transistors

In order to enhance the performance of regioregular poly(3-hexylthiophene) (RR-P3HT) field-effect transistors (FETs), RR-P3HT FETs are prepared by the spin-coating method followed by vacuum placement and annealing. This paper reports that the crystal structure, the molecule interconnection, the surface morphology, and the charge carrier mobility of RR-P3HT films are affected by vacuum relaxation and annealing. The results reveal that the field-effect mobility of RR-P3HT FETs can reach 4.17×10^ - 2~m²/(V.s) by vacuum relaxation at room temperature due to an enhanced local self-organization. Furthermore, it reports that an appropriate annealing temperature can facilitate the crystal structure, the orientation and the interconnection of polymer molecules. These results show that the field-effect mobility of device annealed at 150~℃ for 10 minutes in vacuum at atmosphere and followed by placement for 20 hours in vacuum at room temperature is enhanced dramatically to 9.00×10^ - 2 ~cm²/(V.s).     

发光学及其新进展

发光是一种物体把吸收的能量,不经过热的阶段,直接转换为有选择性的特征辐射的现象.这和处于热平衡状态的物体所发出的热辐射是不同的.例如,采色电视荧光屏的发光,是屏上的发光材料吸收了电子射线的能量直接转换而来的;而普通白炽电灯的光则是热辐射,是电流使灯丝产生焦耳热,灯丝温度升高而变亮的.虽然对发光现象的研究早在十七世纪就已开始,而且有不少的著名科学家,如伽利略、波义耳、牛顿、贝克勒、连纳尔德、斯托克斯、韦德曼等参与了这一领域的工作,甚至得到了像斯托克斯定则这类带有普遍意义的结果(这个定则告诉我们,发光的波长一般总…     

ZnS:Mn,Sm材料中Mn中心与不同的Sm中心的相互作用及温度的影响

本文系统地研究了硫化锌材料中Mn中心与不同的Sm中心的相互作用.证实了Mn中心与不同的Sm中心的相互作用存在很大的差异.另外在77-500K温度范围内测量了Mn中心和Sm中心的发射光谱,发现温度对它们之间的能量传递有着重要的影响.     

CdSe/CdS核/壳型纳米晶的光谱特性

以巯基乙酸为稳定剂制备了CdSe/CdS核／壳型纳米晶。用光吸收谱（Abs)、光致发光谱（PL）及光致发光激发谱（PLE）研究了CdS壳层对CdSe纳米晶电子结构，从而对其吸收和发光性能的影响。根据PL和PLE的结果以及带边激子精细结构的计算结果，我们用尺寸很小的纳米晶中所形成的基激缔合物解释了PL光谱与吸收边之间较大的Stokes位移。     

基于量子点和MEH-PPV的白光发光二极管的研究

利用无机纳米材料与有机聚合物材料相结合的方法制备白光发光二极管器件, 研究了蓝光量子点QDs(B)掺杂聚[2-甲氧基-5-(2-乙基己氧基-1, 4-苯撑乙烯撑](MEH-PPV) 复合体系的发光特性及量子点QDs(B) 掺杂浓度(质量分数)不同对器件发光特性的影响. 制备了ITO/PEDOT:PSS/MEH-PPV:QDs(B)/LiF/Al 结构的电致发光器件, 测试了器件的电致发光光谱和电学、光学特性. 当QDs掺杂浓度为40%, 驱动电压为8 V时器件能得到较为理想的白光发射. 同时, 对比研究了非掺杂体系的发光特性, 制备了结构为ITO/PEDOT:PSS/MEH-PPV/QDs(B)/LiF/Al的器件, 掺杂体系相较于非掺杂体系, 器件的最大亮度增大, 启亮电压降低, 并分析了掺杂体系器件性能改善的原因.     

Study on characteristics of a double-conductible channel organic thin-films transistor with an ultra-thin hole-blocking layer

The properties of top-contact organic thin-film transistors (TC-OTFTs) using ultra-thin 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) as a hole-blocking interlayer have been improved significantly and a BCP interlayer was inserted into the middle of the pentacene active layer. This paper obtains a fire-new transport mode of an OTFT device with double-conductible channels. The accumulation and transfer of the hole carriers are limited by the BCP interlayer in the vertical region of the channel. A huge amount of carriers is located not only at the interface between pentacene and the gate insulator, but also at the two interfaces of pentacene/BCP interlayer and pentacene/gate insulator, respectively. The results suggest that the BCP interlayer may be useful to adjust the hole accumulation and transfer, and can increase the hole mobility and output current of OTFTs. The TC-OTFTs with a BCP interlayer at V_DS=-20~V showed excellent hole mobility μ_FE and threshold voltage V_TH of 0.58~cm²/(V\cdots) and --4.6~V, respectively.