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991.
Philip Schulz Leah L. Kelly Paul Winget Hong Li Hyungchul Kim Paul F. Ndione Ajaya K. Sigdel Joseph J. Berry Samuel Graham Jean‐Luc Brédas Antoine Kahn Oliver L. A. Monti 《Advanced functional materials》2014,24(46):7381-7389
The interfacial electronic structure between oxide thin films and organic semiconductors remains a key parameter for optimum functionality and performance of next‐generation organic/hybrid electronics. By tailoring defect concentrations in transparent conductive ZnO films, we demonstrate the importance of controlling the electron transfer barrier at the interface with organic acceptor molecules such as C60. A combination of electron spectroscopy, density functional theory computations, and device characterization is used to determine band alignment and electron injection barriers. Extensive experimental and first principles calculations reveal the controllable formation of hybridized interface states and charge transfer between shallow donor defects in the oxide layer and the molecular adsorbate. Importantly, it is shown that removal of shallow donor intragap states causes a larger barrier for electron injection. Thus, hybrid interface states constitute an important gateway for nearly barrier‐free charge carrier injection. These findings open new avenues to understand and tailor interfaces between organic semiconductors and transparent oxides, of critical importance for novel optoelectronic devices and applications in energy‐conversion and sensor technologies. 相似文献
992.
993.
根据分子运动论,对水气分子在低渗透岩石中的扩散模式进行研究,得出水气分子中的主要气体H2O、CO2以及O2在新鲜二长岩和玄武岩中的扩散为过渡型扩散.通过计算得到三者的有效扩散系数.以微砂质细粒长石石英砂岩为研究对象,在电子显微镜下获得砂岩的铸体薄片图像,并对其进行处理,建立砂岩的二维孔隙扩散模型,模拟岩石风化过程中水气分子在砂岩孔隙内的扩散过程,得到砂岩模型内部的速度分布图、压力分布图和雷诺数图.结果表明,天然状态下,水气分子的流动主要出现在胶结物受腐蚀的风化区域.胶结物溶蚀产生的贯通孔隙是水气分子的主要扩散通道和贮存场所.水气分子在砂岩内部孔隙中的流动符合流体流动的基本规律,雷诺数的量级为10-3,流动状态为层流.同时对风化岩石的剖面进行分带,分析了水气分子扩散对岩石风化产生的影响. 相似文献
994.
Jesse R. Manders Sai‐Wing Tsang Michael J. Hartel Tzung‐Han Lai Song Chen Chad M. Amb John R. Reynolds Franky So 《Advanced functional materials》2013,23(23):2993-3001
The detailed characterization of solution‐derived nickel (II) oxide (NiO) hole‐transporting layer (HTL) films and their application in high efficiency organic photovoltaic (OPV) cells is reported. The NiO precursor solution is examined in situ to determine the chemical species present. Coordination complexes of monoethanolamine (MEA) with Ni in ethanol thermally decompose to form non‐stoichiometric NiO. Specifically, the [Ni(MEA)2(OAc)]+ ion is found to be the most prevalent species in the precursor solution. The defect‐induced Ni3+ ion, which is present in non‐stoichiometric NiO and signifies the p‐type conduction of NiO, as well as the dipolar nickel oxyhydroxide (NiOOH) species are confirmed using X‐ray photoelectron spectroscopy. Bulk heterojunction (BHJ) solar cells with a polymer/fullerene photoactive layer blend composed of poly‐dithienogermole‐thienopyrrolodione (pDTG‐TPD) and [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM) are fabricated using these solution‐processed NiO films. The resulting devices show an average power conversion efficiency (PCE) of 7.8%, which is a 15% improvement over devices utilizing a poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL. The enhancement is due to the optical resonance in the solar cell and the hydrophobicity of NiO, which promotes a more homogeneous donor/acceptor morphology in the active layer at the NiO/BHJ interface. Finally, devices incorporating NiO as a HTL are more stable in air than devices using PEDOT:PSS. 相似文献
995.
Jung-Ja Yang Rafal Spirydon Tae-Yeon Seong S. H. Lee G. B. Stringfellow 《Journal of Electronic Materials》1998,27(10):1117-1123
Transmission electron diffraction (TED) and transmission electron microscope (TEM) studies have been made of organometallic
vapor phase epitaxial GaxIn1−xP layers (x ≈ 0.5) grown at temperatures in the range 570–690°C to investigate ordering and ordered domain structures. TED
and TEM examination shows that the size and morphology of ordered domains depend on the growth temperature. The ordered domains
change from a fine rod-like shape to a plate-like shape as the growth temperature increases. The domains are of width 0.6∼2
nm and of length 1∼10 nm. Characteristic diffuse features observed in TED patterns are found to depend on the growth temperature.
Extensive computer simulations show a direct correlation between the ordered domain structures and such diffuse features.
A possible model is suggested to describe the temperature dependence of the ordered domain structure. 相似文献
996.
997.
P. Mitra Y. L. Tyan F. C. Case R. Starr M. B. Reine 《Journal of Electronic Materials》1996,25(8):1328-1335
Controlled and effective p-type doping is a key ingredient forin situ growth of high performance HgCdTe photodiode detectors. In this paper, we present a detailed study of p-type doping with
two arsenic precursors in metalorganic chemical vapor deposition (MOCVD) of HgCdTe. Doping results from a new precursortris-dimethylaminoarsenic (DMAAs), are reported and compared to those obtained from tertiarybutylarsine (TBAs). Excellent doping
control has been achieved using both precursors in the concentration range of 3 × 1015-5 × 1017 cm−3 which is sufficient for a wide variety of devices. Arsenic incorporation efficiency for the same growth temperature and partial
pressure is found to be higher with DMAAs than with TBAs. For doping levels up to 1 × 1017 cm−3, the alloy composition is not significantly affected by DMAAs. However, at higher doping levels, an increase in the x-value
is observed, possibly as a result of surface adduct formation of DMAAs dissociative products with dimethylcadmium. The activation
of the arsenic as acceptors is found to be in the 152–50% range for films grown with DMAAs following a stoichiometric anneal.
However, a site transfer anneal increases the acceptor activation to near 100%. Detailed temperature dependent Hall measurements
and modeling calculations show that two shallow acceptor levels are involved with ionization energies of 11.9 and 3.2 meV.
Overall, the data indicate that DMAAs results in more classically behaved acceptor doping. This is most likely because DMAAs
has a more favorable surface dissociation chemistry than TBAs. Long wavelength infrared photodiode arrays were fabricated
on P-on-n heterojunctions, grownin situ with iodine doping from ethyl iodide and arsenic from DMAAs on near lattice matched CdZnTe (100) substrates. At 77K, for
photodiodes with 10.1 and 11.1 (im cutoff wavelengths, the average (for 100 elements 60 × 60 μm2 in size) zero-bias resistance-area product, R0A are 434 and 130 ohm-cm2, respectively. Quantum efficiencies are ≥50% at 77K. These are the highest R0A data reported for MOCVDin situ grown photodiodes and are comparable to state-of-the-art LPE grown photodiodes processed and tested under identical conditions. 相似文献
998.
氮化硅平台阵列波导光栅(AWG)波分(解)复用器具有损耗低、集成度高、温度敏感性低等优势。基于联合微电子中心有限责任公司(CUMEC)的氮化硅集成光子工艺平台,从波导传输损耗、阵列波导与平板波导模式转换损耗、截断损耗、泄漏损耗等方面对氮化硅基AWG波光(解)复用器插入损耗进行了优化,并采用标准CMOS工艺完成低损耗C波段AWG密集波分(解)复用器制备。该氮化硅基AWG密集波分(解)复用器输出通道数为16,输出通道频率间隔200 GHz。测试结果表明,该AWG波分(解)复用器的平均插入损耗为2.34 dB,1 dB带宽为0.44 nm,3 dB带宽为0.76 nm,串扰约为-28 dB。芯片尺寸为850μm×1700μm,较平面光波导(PLC)基AWG大大减小。 相似文献
999.
J. Antoszewski D. J. Seymour L. Faraone J. R. Meyer C. A. Hoffman 《Journal of Electronic Materials》1995,24(9):1255-1262
A quantitative mobility spectrum analysis (QMSA) of experimental Hall and resistivity data as a function of magnetic field
is presented. This technique enables the conductivity contribution of bulk majority carriers to be separated from that of
other species such as thermally generated minority carriers, electrons, and holes populating n and p doped regions, respectively,
and two-dimensional species at surfaces and interface layers. Starting with a suitable first trial function such as the Beck
and Anderson mobility spectrum analysis (MSA), a variation on the iterative procedure of Dziuba and Gorska is used to obtain
a mobility spectrum which enables the various carrier species present in the sample to be identified. The QMSA algorithm combines
the fully automated execution and visually meaningful output format of MSA with the quantitative accuracy of the conventional
least-squares multi-carrier fitting procedure. Examples of applications to HgCdTe infrared detector materials and InAs/GaSb
quantum wells are discussed. The ultimate goal of this paper is to provide an automated, universal algorithm which may be
used routinely in the analysis and interpretation of magneto-transport data for diverse semiconductor materials and bandgap
engineered structures. 相似文献
1000.
Zuoquan Jiang Zhongyin Liu Chuluo Yang Cheng Zhong Jingui Qin Gui Yu Yunqi Liu 《Advanced functional materials》2009,19(24):3987-3995
A series of fluorene‐based oligomers with novel spiro‐annulated triarylamine structures, namely DFSTPA, TFSTPA, and TFSDTC, are synthesized by a Suzuki cross‐coupling reaction. The spiro‐configuration molecular structures lead to very high glass transition temperatures (197–253 °C) and weak intermolecular interactions, and consequently the structures retain good morphological stability and high fluorescence quantum efficiencies(0.69–0.98). This molecular design simultaneously solves the spectral stability problems and hole‐injection and transport issues for fluorene‐based blue‐light‐emitting materials. Simple double‐layer electroluminescence (EL) devices with a configuration of ITO/TFSTPA (device A) or TFSDTC (device B)/ TPBI/LiF/Al, where TFSTPA and TFSDTC serve as hole‐transporting blue‐light‐emitting materials, show a deep‐blue emission with a peak around 432 nm, and CIE coordinates of (0.17, 0.12) for TFSTPA and (0.16, 0.07) for TFSDTC, respectively, which are very close to the National Television System Committee (NTSC) standard for blue (0.15, 0.07). The maximum current efficiency/external quantum efficiencies are 1.63 cd A?1/1.6% for device A and 1.91 cd A?1/2.7% for device B, respectively. In addition, a device with the structure ITO/DFSTPA/Alq3/LiF/Al, where DFSTPA acts as both the hole‐injection and ‐transporting material, is shown to achieve a good performance, with a maximum luminance of 14 047 cd m?2, and a maximum current efficiency of 5.56 cd A?1. These values are significantly higher than those of devices based on commonly usedN,N′‐di(1‐naphthyl)‐N,N′‐diphenyl‐[1,1′‐biphenyl]‐4,4′‐diamine (NPB) as the hole‐transporting layer (11 738 cd m?2 and 3.97 cd A?1) under identical device conditions. 相似文献