碳纳米管阴极平板显示器的工艺研究

碳纳米管场致发射显示器是一种新型的真空器件，也是一种具有巨大应用潜力的平板型显示设备。本文详细地介绍了碳纳米管场致发射原理，给出了碳纳米管阴极平板显示器的基本结构和工作原理，对于显示器件的真空封装，碳纳米管阴极装配，控制栅极制作等工艺问题进行了阐述和研究。采用这些技术，已经研制出了碳纳米管阴极场致发射显示器的样品。     

有机层界面电荷聚集及其对OLED性能的影响

采用金属Al、合金Mg:Ag以及复合层LiF-Al作为阴极材料,利用真空加热蒸镀法制备了异质结有机发光器件(OLED),研究了阴极材料与器件有机层界面电荷聚集之间的关系.结果表明,界面电荷聚集与阴极材料密切相关,LiF-Al复合层阴极器件的界面聚集电荷最少,而Al金属阴极器件的界面聚集电荷最多.同时,通过测试器件的光电性能,进一步研究了阴极材料对OLED发光特性的影响.实验结果显示,LiF-Al复合层阴极器件具有最大的发光亮度和效率、最小的启亮电压和驱动电压.     

TE光电阴极制作技术的研究

对ＴＥ光电阴极制作工艺中存在的肖特基结热退化现象以及为了实现ＴＥ阴极器件化，设计了超高真空激活系统和制作工艺流程，并采用ＰＥＣＶＤ－Ｓｉ３Ｎ４绝缘膜和多次蒸银方法彻底消除了热退化现象，从而实现在真空系统内场助电极的原位连接和阴极的激活，为实现ＴＥ光电阴极器件的分离打下基础。     

热处理对MEH—PPV有机电致发光性能的影响

以MEH-PPV为发光层的单层聚合物有机发光二极管（OLED）器件在不同条件下进行真空热处理，并用金相显微镜观察器件在12V电压下工作的阴极表面形貌。与未经处理的器件相比，处理后的器件阴极表面的气泡及黑斑明显减少；器件的最大相对发光强度提高了一个数量级；启亮电压降低了2.0V；半寿命提高了12．7倍。初步分析表明，其主要原因在于，一方面有效地减少了器件在工作过程中由于焦耳热产生的有害气体，从而减少了阴极表面气泡及黑斑的出现；另一方面，热处理方法也增强了有机发光层与阴极接触界面的结合力，提高电子的注入能力。     

场发射金属尖阵列的研究

本文介绍了真空微电子器件场发射金属尖阵列阴极的制备工艺技术。采用硅的各向异性腐蚀工艺（反向）和浓硼腐蚀自停止工艺制备成功金属尖阵列，这为今后研制金属阴极真空微电子器件开拓了新途径     

新型前栅极CNT-FED的研究

传统的前栅极场致发射显示板由于介质层和栅极的制作在生成或制作阴极场致发射源之后，在制造过程中容易破坏场致发射源；另外阴极发射对介质层厚度、阳极电压和调制极开口等参数非常敏感，所以器件的发射均匀性难以保证。为了解决这些问题，引入了类似HOP玻璃的结构。阴极上只需要丝印碳纳米管，无需制作介质层和栅极，解决了场致发射源被破坏的问题。阴极与栅极之间真空取代了介质层，由于真空的绝缘性能高于介质层，所以阴极与栅极之间的距离可以减小，栅极的调制效果更显著。由于玻璃的平整度高于一般方法制作的介质层的平整度，所以器件的发射均匀性比较好。     

钙铝合金作为阴极对OLED器件性能的影响

为了研究阴极材料对有机电致发光器件的影响,在不改变其他功能层的情况下,分别采用不同比例的Ca/Al合金和纯Al作为器件的阴极制备了4种绿光OLED器件,器件结构分别为:ITO/2T-NATA(15nm)/NPB(25nm)/Alq3:C545T(20nm)/Alq3(30nm)/Ca(X%):Al(100nm)和ITO/2T-NATA(15nm)/NPB(25nm)/Alq3:C545T(20nm)/Alq3(30nm)/Al(100nm)。从电流-电压、电压-亮度、器件的外量子效率和光谱特性等几个方面,对不同比例的Ca/Al合金作为阴极的器件与Al作为阴极的器件进行了对比分析,发现当Ca的质量分数为10%时,器件的亮度达到最大值10100cd/m2,并且器件的效率最高。对上述现象产生的原因进行了探讨,分析了器件光谱与不同阴极和不同驱动电流间的关系,从机理上阐述了OLED器件阴极的选取准则。     

场发射金属尖陈列的研究

本文介绍了真空微电子器件场发射金属尖陈列阴极的制备工艺技术。采用硅的各向异性腐蚀工艺（反向）和浓硼腐蚀自停止工艺制备成功金属尖陈列，这为今后研制金属阴极真空微电子器件开拓了新途径。     

Ni海绵氧化物阴极制备技术改进

采用喷砂和真空蒸散技术，改进了Ni海绵氧化物阴极制备方法。试验表明，这一改进可显著提高阴极制备质量，有利于提高大功率微波器件的可靠性。     

氧化物阴极的应用研究及发展

氧化物阴极是真空器件应用最广泛的热阴极,为了满足微波器件向高功率、宽频带、长寿命等技术要求的持续发展,提高氧化物阴极的直流及宽脉冲发射电流密度、增强它的稳定可靠性一直是氧化物阴极应用研究的主题。本文主要论述氧化物阴极电子发射过程、分析氧化物阴极存在问题根源及解决的方法,研制出新型氧化物阴极,给出了阴极直流、脉冲、寿命性能以及在高功率速调管和行波管的应用,展望了它的应用前景。     

Carrier transport mechanism in La-incorporated high-k dielectric/metal gate stack MOSFETs

In this paper, carrier transport mechanism of MOSFETs with HfLaSiON was analyzed. It was shown that gate current is consisted of Schottky emission, Frenkel-Poole (F-P) emission and Fowler-Nordheim (F-N) tunneling components. Schottky barrier height is calculated to be 0.829 eV from Schottky emission model. Fowler-Nordheim tunneling barrier height was 0.941 eV at high electric field regions and the trap energy level extracted using Frenkel-Poole emission model was 0.907 eV. From the deviation of weak temperature dependence for gate leakage current at low electric field region, TAT mechanism is also considered.     

Clean galena, contaminated lead, and soft errors in memory chips

Lead (Pb) disks were exposed to a radon (Rn)-rich atmosphere and surface alpha particle emissions were detected over time. Cumulative ²¹⁰Po alpha emission increased nearly linearly with time. Conversely, cumulative emission for each of ²¹⁸Po and ²¹⁴Po was constant after one and two hours, respectively. Processing of radiation-free Pb ore (galena) in inert atmospheres was compared with processing in ambient air. Galena processed within a flux heated in a graphite crucible while exposed to an inert atmosphere, resulted in lead contaminated with ²¹⁰Po (Trial 1). A glove box was next used to prepare a baseline radiation-free flux sample in an alumina crucible that was heated in an oven with an inert atmosphere (Trials 2 and 3). Ambient air was thereafter introduced, in place of the inert atmosphere, to the radiation-free flux mixture during processing (Trial 4). Ambient air introduced Rn and its progeny (RAD) into the flux during processing so that the processed Pb contained Po isotopes. A typical coke used in lead smelting also emitted numerous alpha particles. We postulate that alpha particles from tin/lead solder bumps, a cause of computer chip memory soft errors, may originate from Rn and RAD in the ambient air and/or coke used as a reducing agent in the standard galena smelting procedure. Author’s Note: No-alpha lead (NAL) as used in this article is a misnomer. What is meant is lead in which the alpha particle (α) emission is so low that it cam not be detected with current instrumentation and t memory chips are not affected by α emission from lead solder bumps.     

Measurement of surface recombination velocity and bulk lifetime in Si wafers by the kinetics of excess thermal emission

A contactless nondestructive technique for measuring recombination parameters (surface recombination velocity and bulk and effective lifetime of free carriers) in Si wafers is proposed. The technique is based on the analysis of the relaxation kinetics of excess thermal emission of a wafer beyond the Si intrinsic absorption edge (λ > 3 μm) after excitation by a short laser pulse with a photon energy higher than the Si band gap. Experimental results for wafers 300 μm and 2 mm thick, excited by laser radiation with wavelengths of 0.96 and 1.06 μm at above-room temperatures are presented. The surface and bulk components of the effective lifetime are separated by extrapolating the final portion of the kinetics of excess thermal emission relaxation to the intersection with the y coordinate axis.     

Characteristics of GaN stripes grown by selective-area metalorganic chemical vapor deposition

We report on the selective-area metalorganic chemical vapor deposition of GaN stripes in the size range of 50 to 125 urn and the characterization of the morphology, topography, and optical properties of these stripes. GaN films (∼1–3 μm) grown on (0001) sapphire are used as the substrates. Excellent surface morphology is achieved under optimized growth conditions which include a higher V/III ratio than broad area growth. It is found that, under certain growth conditions, (0001) terraces of ~5 μm in width develop at the edges of all stripes, independent of stripe size and orientation. The selectively grown GaN yields stronger band-edge emission than the “substrate” GaN which indicates an improvement in optical quality. However, the donor-acceptor pair recombination (or conduction band to acceptor transition) and yellow emission are also enhanced in certain areas of the stripes. The spatial correlation of these emission bands is established by cathodoluminescence wavelength imaging, and the origin of these emissions is speculated.     

1.46 μm room-temperature emission from InAs/InGaAs quantum dot nanostructures

We present a study on InAs/InGaAs QDs nanostructures grown by molecular beam epitaxy on InGaAs metamorphic buffers, that are designed so as to determine the strain of QD and, then, to shift the luminescence emission towards the 1.5 μm region （QD strain engineering）. Moreover, we embed the QDs in InAIAs or GaAs barriers in addition to the InGaAs confining layers, in order to increase the activation energy for confined carrier thermal escape; thus, we reduce the thermal quenching of the photoluminescence, which prevents room temperature emission in the long wavelength range. We study the dependence of QD properties, such as emission energy and activation energy, on barrier thickness and height and we discuss how it is possible to compensate for the barrier-induced QD emission blue-shift taking advantage of QD strain engineering. Furthermore, the combination of enhanced barriers and QD strain engineering in such metamorphic QD nanostmctures allowed us to obtain room temperature emission up to 1.46μm, thus proving how this is a valuable approach in the auest for 1.55 um room temperature emission from ODs grown on GaAs substrates.     

Thermal annealing effect on light emission profile of polyfluorenes containing double bond subunit

We presented comprehensive photoluminescence (PL) and electroluminescence (EL) studies of polyfluorene based electroactive polymer (SF4) containing double bond side chain to investigate its characteristics as a function of temperature. Annealing treatment was conducted for thin films on glass substrates and also for the organic light emitting diodes (OLEDs) at different temperatures. While polymer thin film coated on to glass substrate annealed at < 150 °C exhibited green color emission, OLEDs that annealed at >150 °C shifted white color emission. It was implying that the emission was taking place interchain interaction. Phase modulation at higher annealing temperatures was occurred on the thin film as shown AFM images. Further, annealed polymer film with 120 °C exhibited the best performance in OLED device with luminance 5241 cd m⁻², a maximum efficiency 1.54 cd A⁻¹ and external quantum efficiency 0.54% compared to other polymer films annealed with different temperatures.     

Blue electroluminescence in forward-biased ZnSe diodes

The electroluminescence emission spectrum of forward-biased MIS diodes prepared on high-purity single-crystal ZnSe has been studied over the temperature range 20-290 K. At room temperature the emission consisted of two intense bands in the blue at 4655 and 4770 Å, while at the lowest temperatures much more structure was observed. Thus at 20 K free and bound exciton emission was particularly intense, and the donor-acceptor (DA) pair band emission (the Q series), together with its accompanying free-to-bound series was also prominent. The bound exciton, pair band, and free-to-bound emission were all substantially quenched as the temperature was increased, so that at room temperature the two blue bands were the only remaining components of the luminescence. Evidence is produced to demonstrate that the band at 4655 Å is associated with free exciton recombination following scattering from free electrons in the conduction band. The band at 4770 Å is attributed to free exciton recombination with the emission of two longitudinal optical (LO) phonons.     

Synthesis and optoelectronic properties of novel fluorene-bridged dinuclear cyclometalated iridium (III) complex with A–D–A framework in the single-emissive-layer WOLEDs

To explore the influence of push–pull chromophores on properties of emitter in organic light-emitting devices (OLEDs), an acceptor–donor–acceptor (A–D–A)-based dinuclear iridium (III) complex of (dfppy)₄Ir₂(dipic-FL) was synthesized via Suzuki coupling reaction, in which dfppy is 2-(2,4-difluorophenyl)pyridine and dipic-FL is 2,7-di(5-pyridyl-2-carboxyl)-9,9-dioctyl-9H-fluorene. An intense emission peak at about 480 nm resulting from the (dfppy)₂Ir(pic) chromophore and a weak long-wavelength emission band at 580–660 nm attributed to intramolecular charge transfer transition were exhibited for (dfppy)₄Ir₂(dipic-FL) in dichloromethane solution. But a remarkably hypsochromic photoluminescence profile with an intense characteristical emission peak at 422 nm was observed, which is attributed to the intraligand (IL) π–π^∗ excited states in its thin film. White emission with a maximum luminance of 1040 cd/m² and current efficiency of 1.2 cd/A was obtained in its single-emissive-layer (SEL) OLEDs with a configuration of ITO/PEDOT:PSS/(dfppy)₄Ir₂(dipic-FL) (10 wt%):TCTA/TPBi/LiF/Al. To our knowledge, this is one of the best examples in term of dinuclear iridium complex as single dopant in the high-performance white-emitting SEL-OLEDs.     

Voltage independent white emission from all solution processed polymer light-emitting diode with dual emitting layers spaced by an alcohol soluble conjugated polymer as interlayer

Spatial control of recombination zone in multilayer white polymer light emitting diode (WPLED) is highly desirable for stable white-light emission. In this work, the utilization of 18-crown-6 (Cn6)-grafted polyfluorene (PFCn6) as an interlayer in between two emitting layers is demonstrated to control the recombination zones for the multilayer WPLED with β-phase and rubrene doped poly(9,9-di-n-octylfluorene) (PFO) as blue- and yellow-emitting layers, respectively. The device gives the maximum brightness of 15,695 cd/m² and maximum efficiency 5.43 cd/A, accompanying with voltage-independent electroluminescence spectrum having invariant Commission Internationale de L’Eclairage (CIE) coordinates of (0.32, 0.36). The performance with the luminance efficiency 5.43 cd/A and voltage independent white emission is the highest record among the reported multilayer WPLED.     

Significance of irreversible formation of “electromer” in 1-bis[4-[N,N-di(4-tolyl)amino]phenyl]-cyclohexane layer associated with the stability of deep blue phosphorescent organic light emitting diodes

We demonstrate that injection of electrons in 1-bis[4-[N,N-di(4-tolyl)amino]phenyl]-cyclohexane (TAPC) layer irreversibly induces defect sites responsible for “electromer” emission. We also show that the defects alter the charge transporting properties of TAPC layer to influence the charge balance of iridium(III)[bis(4,6-difluorophenyl)pyridinato-N,C^2′]tetrakis(1-pyrazolyl)borate (FIr6) based deep blue phosphorescent organic light emitting diodes (PHOLED). The present investigation implies that deep-blue PHOLEDs should be carefully designed for the emission zone to be located far enough from the TAPC layer so as to avoid or minimize the emission from TAPC layer.