新型平板显示器技术 聚合物基板上的有机薄膜晶体管(TFT)

近年来,有机薄膜晶体管(OTFT)发展非常迅速,它与无机TFT相比有两个突出的优点:一是制作温度低,二是成本低;而且,有机薄膜晶体管还具有比硅晶体管更好的柔韧性。适合用于有源矩阵显示器、智能卡、商品价格及存货分类标签、大面积传感阵列等应用领域。并五苯(pentacene)是目前制作性能稳定的有机薄膜晶体管的常用材料,它是一种有机材料,表现出相当于非晶硅的高迁移性。但是,并五苯必须在真空状态下加工,且保存寿命不长,在受控制的实验室环境中最多能保存一年。虽然它有这些局限性,但却是迄今为止科学家们发现的最理想的研究材料。由美国政…     

并五苯有机薄膜晶体管电学性能研究

制作了以并五苯为半导体有源层材料的有机薄膜晶体管。用热氧化的方法制备了一层230nm的二氧化硅栅绝缘层并用原子力显微镜(AFM)分析了表面形貌。研究了器件的电学性能,得到的并五苯有机薄膜晶体管器件载流子迁移率为8.9×10-3cm2/V.s,器件的阈值电压和开关电流比分别为-8.2V和1.0×104。     

有机薄膜晶体管在电子技术中的应用及挑战

有机薄膜晶体管（0TFT）是有机电子学的一个重要的研究分支。本文介绍了有机薄膜晶体管的科学技术发展水平,其在电子技术各领域的应用及挑战,评述了该领域的研究进展,并对其前景进行了展望。     

非晶硅薄膜晶体管有机电致发光单元像素的设计

介绍了两管薄膜晶体管(TFT)和四管TFT有源驱动有机发光二极管工作原理,结合TFT工作条件限制以及实现显示的要求完成了四管TFT有源驱动有机电致发光单元像素的设计,利用Hspice软件验证了单元像素的设计结果,最大输出电流为2.1 μA,一帧的时间后变化到2.0 μA,变化量小于一个灰阶电流,满足显示要求.     

有机薄膜晶体管阵列面向电子纸像素设计

讨论了有机薄膜晶体管(Organic Thin Film Transistor,OTFT)作为开关器件来驱动电子纸的像素设计,特别是像素电路结构、HSPICE模拟用模型参数和像素平面结构。讨论了有机薄膜晶体管制造过程,并用HSPIC模拟分析了有机薄膜晶体管结构和存贮电容大小对像素波形的影响,结果表明TFT结构的选择依赖于存贮电容的大小。     

石墨烯电极有机薄膜晶体管研究

利用化学气相沉积法生长的高性能的层状石墨烯,通过转移和图案化后用作电极,制备了底接触的并五苯有机薄膜晶体管(OTFTs)。原子力显微镜观察发现,石墨烯电极的厚度比一般的金电极薄的多,所以石墨烯电极厚度对并五苯晶粒的生长影响不大。电学性能研究得到器件的输出和转移曲线、开关电流比、阈值电压、场效应迁移率。转移曲线的关态电流约为10-9 A,电流的开关比超过103。基于底接触的并五苯OTFTs的最大场效应迁移率约2×10-2 cm2.V-1.s-1。     

新型平板显示器技术

近年来，有机薄膜晶体管(OTFT)发展非常迅速，它与无机TFT相比有两个突出的优点：一是制作温度低，二是成本低；而且，有机薄膜晶体管还具有比硅晶体管更好的柔韧性。适合用于有源矩阵显示器、智能卡、商品价格及存货分类标签、大面积传感阵列等应用领域。     

非晶硅薄膜晶体管聚合物发光二极管--用于未来的平板电视

近年来,PLED（聚合物发光二极管）和a-Si TFT（非晶硅薄膜晶体管）技术取得了巨大进展,两者的结合有望成为未来平板电视的主流.三星与杜邦公司已经研制成功14.1英寸的非晶硅薄膜晶体管聚合物发光二极管（a-Si TFT AM-PLED）全彩显示面板.本文介绍该a-Si TFTAMpLED的制作过程,讨论它独特的性能和成本优势,并分析未来平板电视的发展趋势.     

敬请您的产品乘坐我们的现代电子技术快车——《现代电子技术》诚征广告

近日，京东方科技集团与中国惠普有限公司宣布，京东方TFT—LCD(薄膜晶体管液晶显示器件)五代线生产制造自动化系统(CIMS)与企业管理信息化系统(ERP)成功上线。此次南京东方与惠普公司合作实施的中国首例TFT—LCD生产制造自动化及管理信息化系统，成功保证了京东方TFT—LCD五代线在今年五月的量产。     

OTFT-OLED

索尼公司首次开发了OTFT（有机薄膜晶体管）的有源驱动的OLED。采用基板材料是塑料膜，TFT的有源材料和绝缘材料都是有机材料，保证了器件的可弯曲性。开发样机指标如下：     

Pentacene TFT driven AM OLED displays

Pentacene organic thin-film transistors (TFTs)-driven active matrix organic light-emitting diode (OLED) displays has been investigated. This letter addresses several process issues unique to this type of display which are important in achieving bright and uniform displays. A bottom contact structure was used to fabricate the pentacene TFT backplane. Polyvinyl alcohol and parylene were used to isolate the pentacene active layer and passivate the backplane. The low processing temperature may allow the use of polymeric substrates and lower cost processing. Uniform TFT performance is achieved with reasonably good mobility and on/off ratio on the backplane. The initial OLED display performance is also presented.     

Highly Sensitive Non‐Classical Strain Gauge Using Organic Heptazole Thin‐Film Transistor Circuit on a Flexible Substrate

A non‐classical organic strain gauge as a voltage signal sensor is reported, using an inverter‐type thin‐film transistor (TFT) circuit, which is able to sensitively measure a large quantity of elastic strain (up to ≈2.48%), which approaches an almost folding state. Novel heptazole‐based organic TFTs are chosen to be incorporated in this gauge circuit; organic solid heptazole has small domain size in general. While large crystal domain‐pentacene TFTs seldom show sufficient current variation upon mechanical bending for tensile strain, these heptazole TFTs demonstrate a significant variation for the same strain condition as applied to pentacene devices. In addition, the pentacene channel does not recover to its original electric state after bending but heptazole channels are very elastic and reversible, even after going through serious bending. More interesting is that the heptazole TFTs show only a little variation of signal current under horizontal direction strain, while they make a significant amount of current decrease under vertical direction strain. Utilizing the anisotropic response to the tensile bending strain, an ultrasensitive voltage output strain gauge composed of a horizontally and vertically oriented TFT couple is demonstrated.     

薄膜晶体管研究进展

薄膜晶体管是液晶显示器的关键器件，对显示器件的工作性能具有十分重要的作用。本文论述了薄膜晶体管的发展历史，描述了薄膜晶体管的工作原理，分析了非晶硅薄膜晶体管、多晶硅薄膜晶体管、有机薄膜晶体管、ZnO活性层薄膜晶体管的性能结构特点与最新进展，并展望了薄膜晶体管的应用。     

Environmental effects on the electrical behavior of pentacene thin-film transistors with a poly(methyl methacrylate) gate insulator

The electrical properties of top-contact pentacene thin-film transistors (TFTs) with a poly(methyl methacrylate) (PMMA) gate dielectric were analyzed in air and vacuum environments. Compared to the vacuum case, the pentacene TFT in air exhibited lower drain currents and more pronounced shifts in the threshold voltage upon reversal of the gate voltage sweep direction, together with a decrease in the field-effect mobility. These characteristic variations were explained in terms of two distinctive actions of polar H₂O molecules in pentacene TFT. H₂O molecules were suggested to diffuse under the source and drain contacts and interrupt the charge injection into the pentacene film, whereas those that permeate at the pentacene/PMMA interface retard hole depletion in and around the TFT channel. The diffusion process was much slower than the permeation process. The degraded TFT characteristics in air could be recovered mostly by storing the device under vacuum, which suggests that the air instability of TFTs is due mainly to the physical adsorption of H₂O molecules within the pentacene film.     

Extended lifetime of pentacene thin-film transistor with polyvinyl alcohol (PVA)/layered silicate nanocomposite passivation layer

We prepared a novel organic passivation material to protect organic thin-film transistors (OTFTs) from H₂O and O₂ using a polyvinyl alcohol (PVA)/hydrophilic layered silicate (HLS) nanocomposite system. Using up to a 3 wt% layered silicate to PVA weight concentration, a highly homogeneous nanocomposite solution was prepared. In addition, a PVA/HLS nanocomposite solution formed a smooth film layer by the spin-coating method with RMS surface roughness of about 1 nm. An OTFT device with PVA passivation showed a decrease of 23% in field effect mobility after passivation. However, a pentacene TFT device with PVA/HLS nanocomposite passivation showed no significant initial performance drop after passivation, and mobility was even slightly improved. Pentacene TFT-passivated PVA/HLS showed 2860 h of TFT lifetime (the time required to reduce the mobility by one-half of the initial mobility after passivation), which is almost twice the lifetime of pentacene TFT with PVA passivation (1320 h). We propose that a layered silicate containing PVA nanocomposite film can be used as an effective organic passivation layer in an OTFT.     

Top gate pentacene thin film transistor with spin-coated dielectric

Fabrication of top gate pentacene thin film transistor (TFT) is made possible with spin-coatable dielectrics by the technique presented here. Such fabrication has been impractical because of the ill effects a solvent can have on pentacene. A bilayer of pentacene on insulator that are coated on a mold is transferred to a glass substrate on which source and drain electrodes are defined. In the transfer process, pentacene is automatically patterned. This fabrication method allows for the channel length to be as small as photolithography would permit.     

Mirrored OLED pixel circuit for threshold voltage and mobility compensation with IGZO TFTs

In this paper, pixel circuit using mirroring structure with Indium–Gallium–Zinc oxide (IGZO) thin film transistors (TFTs) for active matrix organic light emitting diode (AMOLED) display is proposed. This pixel circuit consists of only four TFTs, and one capacitor. Due to the mirroring structure, characteristic of the driving TFT can be precisely sensed by the sensing TFT, which is deployed in a discharging path for gate electrode of the driving TFT. This discharging process is strongly dependent on threshold voltage (V_T) and effective mobility of the sensing TFT. Circuit operating details are discussed, and compensation effects for threshold voltage shift and mobility variations are verified through numerical derivation and SPICE simulations. Furthermore, compared with conventional schematics, the proposed pixel circuit might have much simplified external driving circuits, and it is a promising alternative solution of high performance AMOLED display.     

Spatial Mapping of Morphology and Electronic Properties of Air‐Printed Pentacene Thin Films

To accelerate the pace of materials discovery and application, comprehensive links need to be established between a material's structure, properties, and process conditions used to obtain the material and/or final application format. This work examines the dry printing of pentacene thin film transistor (TFT) channels by guard flow‐enhanced organic vapor jet printing (GF‐OVJP), a technique that enables direct, solvent‐free, additive patterning of device‐quality molecular semiconductors in air. Deposition in air entails non‐trivial effects at the boundary between ambient surroundings and the gas jet carrying the semiconductor vapor that influence the morphology and properties of the resulting electronic devices. Synchrotron X‐ray diffraction is employed, complemented by measurement of electronic properties of GF‐OVJP deposited films in a TFT to reveal how the morphology and electronic properties of the films depend on thickness, location within the printed pattern, nozzle translation velocity, and other process parameters. The hole field‐effect mobility of the printed pentacene film is linked quantitatively with its crystallinity, as well as with extent of exposure to ambient air during deposition. The analysis can be extended to accurately predict the performance of devices deposited in air by GF‐OVJP, which are demonstrated here for a planar, large area deposit.     

A new pixel circuit for driving organic light-emitting diode with low temperature polycrystalline silicon thin-film transistors

A new pixel circuit design for active matrix organic light-emitting diode (AMOLED), based on the low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) is proposed and verified by SPICE simulation. Threshold voltage compensation pixel circuit consisting of four n-type TFTs, one p-type TFT, one additional control signal, and one storage capacitor is used to enhance display image quality. The simulation results show that this pixel circuit has high immunity to the variation of poly-Si TFT characteristics.