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1.
Sayan Bhattacharyya Ilana Perelshtein Ofer Moshe Daniel H. Rich Aharon Gedanken 《Advanced functional materials》2008,18(11):1641-1653
The carbon‐encapsulated, Mn‐doped ZnSe (Zn1−xMnxSe@C) nanowires, nanorods, and nanoparticles are synthesized by the solvent‐free, one‐step RAPET (reactions under autogenic pressure at elevated temperature) approach. The aspect ratio of the nanowires/nanorods is altered according to the Mn/Zn atomic ratio, with the maximum being observed for Mn/Zn = 1:20. A 10–20 nm amorphous carbon shell is evidenced from electron microscopy analysis. The replacement of Zn by Mn in the Zn1−xMnxSe lattice is confirmed by the hyperfine splitting values in the electron paramagnetic resonance (EPR) experiments. Raman experiments reveal that the Zn1−xMnxSe core is highly crystalline, while the shell consists of disordered graphitic carbon. Variable‐temperature cathodoluminescence measurements are performed for all samples and show distinct ZnSe near‐band‐edge and Mn‐related emissions. An intense and broad Mn‐related emission at the largest Mn alloy composition of 19.9% is further consistent with an efficient incorporation of Mn within the host ZnSe lattice. The formation of the core/shell nanowires and nanorods in the absence of any template or structure‐directing agent is controlled kinetically by the Zn1−xMnxSe nucleus formation and subsequent carbon encapsulation. Mn replaces Zn mainly in the (111) plane and catalyzes the nanowire growth in the [111] direction. 相似文献
2.
Preparation of coaxial (core–shell) CdS–ZnS and Cd1–xZnxS–ZnS nanowires has been achieved via a one‐step metal–organic chemical vapor deposition (MOCVD) process with co‐fed single‐source precursors of CdS and ZnS. Single‐source precursors of CdS and ZnS of sufficient reactivity difference were prepared and paired up to form coaxial nanostructures in a one‐step process. The sequential growth of ZnS on CdS nanowires was also conducted to demonstrate the necessity and advantages of the precursor co‐feeding practice for the formation of well‐defined coaxial nanostructures. The coaxial nanostructure was characterized and confirmed by high‐resolution transmission electron microscopy and corresponding energy dispersive X‐ray spectrometry analyses. The photoluminescence efficiencies of the resulting coaxial CdS–ZnS and Cd1–xZnxS–ZnS nanowires were significantly enhanced compared to those of the plain CdS and plain Cd1–xZnxS nanowires, respectively, owing to the effective passivation of the surface electronic states of the core materials by the ZnS shell. 相似文献
3.
Alexandre Ponrouch Sébastien Garbarino Erwan Bertin Carmen Andrei Gianluigi A. Botton Daniel Guay 《Advanced functional materials》2012,22(19):4172-4181
Highly {100} oriented Pt deposits were prepared by electrodeposition from a 10 mM HCl, 100 mM KCl and Na2PtCl6.xH2O electrolyte. The deposits were prepared in the form of thin films and array of nanowires. A qualitative assessment of the proportion of {100} oriented Pt surfaces was obtained through X‐ray diffraction measurements and cyclic voltammetry in 0.5 M H2SO4. The effect of the deposition potential, Edep, temperature of the electrolyte, Tdep, platinum salt concentration [Na2PtCl6.xH2O], and nature of the substrate were investigated. It was shown that the proportion of {100} oriented Pt surfaces reaches a maximum for Edep = ‐0.35 V vs SCE. Moreover, this proportion increases steadily as Tdep and [Na2PtCl6.xH2O] are decreased from 75 to 25 °C and from 2.5 to 0.25 mM, respectively. Scanning electron microscopy and high‐resolution transmission electron microscopy micrographs indicate that the more oriented samples are made of pine tree‐like structures that are effectively single crystals, and that the growth facets appear to be close to the {001} plane. This observation also clearly indicates that the plane exposed during the CV experiment is also {001}. As suggested by these micrographs, the films and nanowires are highly porous and roughness factors as large as 1000 were obtained on highly {100} oriented Pt nanowires. The predominance of {100} facets is attributed to their energetically favoured growth in the presence of hydrogen, and is shown to be significantly enhanced when the mass transport of Pt4+ is limited. Due to the predominance of {100} facets, the normalized electrocatalytic activity (μA cm?2Pt) for the electro‐oxidation of hydrazine and ammonia is higher than non‐oriented polycrystalline Pt by a factor of 4 and 2.7, respectively. 相似文献
4.
Gurpreet S. Selopal Haiguang Zhao Xin Tong Daniele Benetti Fabiola Navarro‐Pardo Yufeng Zhou David Barba François Vidal Zhiming M. Wang Federico Rosei 《Advanced functional materials》2017,27(30)
Colloidal quantum dots (QDs) are widely studied due to their promising optoelectronic properties. This study explores the application of specially designed and synthesized “giant” core/shell CdSe/(CdS)x QDs with variable CdS shell thickness, while keeping the core size at 1.65 nm, as a highly efficient and stable light harvester for QD sensitized solar cells (QDSCs). The comparative study demonstrates that the photovoltaic performance of QDSCs can be significantly enhanced by optimizing the CdS shell thickness. The highest photoconversion efficiency (PCE) of 3.01% is obtained at optimum CdS shell thickness ≈1.96 nm. To further improve the PCE and fully highlight the effect of core/shell QDs interface engineering, a CdSex S1?x interfacial alloyed layer is introduced between CdSe core and CdS shell. The resulting alloyed CdSe/(CdSex S1?x )5/(CdS)1 core/shell QD‐based QDSCs yield a maximum PCE of 6.86%, thanks to favorable stepwise electronic band alignment and improved electron transfer rate with the incorporation of CdSex S1?x interfacial layer with respect to CdSe/(CdS)6 core/shell. In addition, QDSCs based on “giant” core/CdS‐shell or alloyed core/shell QDs exhibit excellent long‐term stability with respect to bare CdSe‐based QDSCs. The giant core/shell QDs interface engineering methodology offers a new path to improve PCE and the long‐term stability of liquid junction QDSCs. 相似文献
5.
Promoting Active Sites in Core–Shell Nanowire Array as Mott–Schottky Electrocatalysts for Efficient and Stable Overall Water Splitting
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Developing earth‐abundant, active, and robust electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) remains a vital challenge for efficient conversion of sustainable energy sources. Herein, metal–semiconductor hybrids are reported with metallic nanoalloys on various defective oxide nanowire arrays (Cu/CuOx, Co/CoOx, and CuCo/CuCoOx) as typical Mott–Schottky electrocatalysts. To build the highway of continuous electron transport between metals and semiconductors, nitrogen‐doped carbon (NC) has been implanted on metal–semiconductor nanowire array as core–shell conductive architecture. As expected, NC/CuCo/CuCoOx nanowires arrays, as integrated Mott–Schottky electrocatalysts, present an overpotential of 112 mV at 10 mA cm?2 and a low Tafel slope of 55 mV dec?1 for HER, simultaneously delivering an overpotential of 190 mV at 10 mA cm?2 for OER. Most importantly, NC/CuCo/CuCoOx architectures, as both the anode and the cathode for overall water splitting, exhibit a current density of 10 mA cm?2 at a cell voltage of 1.53 V with excellent stability due to high conductivity, large active surface area, abundant active sites, and the continuous electron transport from prominent synergetic effect among metal, semiconductor, and nitrogen‐doped carbon. This work represents an avenue to design and develop efficient and stable Mott–Schottky bifunctional electrocatalysts for promising energy conversion. 相似文献
6.
Jun Xu Weixin Zhang Zeheng Yang Shaixia Ding Chunyan Zeng Lingling Chen Qiang Wang Shihe Yang 《Advanced functional materials》2009,19(11):1759-1766
By a facile water evaporation process without adding any directing agent, Cu2‐xSe nanowire bundles with diameters of 100–300 nm and lengths up to hundreds of micrometers, which comprise crystalline nanowires with diameters of 5–8 nm, are obtained. Experiments reveal the initial formation/stacking of CuSe nanoplates and the subsequent transformation to the Cu2‐xSe nanowire bundles. A water‐evaporation‐induced self‐assembly (WEISA) mechanism is proposed, which highlights the driving force of evaporation in promoting the nanoplate stacking, CuSe‐to‐Cu2‐xSe transformation and the growth/bundling of the Cu2‐xSe nanowires. The simplicity, benignancy, scalability, and high‐yield of the synthesis of this important nanowire material herald its numerous applications. As one example, the use of the Cu2‐xSe nanowire bundles as a photoluminescence‐type sensor of humidity is demonstrated, which shows good sensitivity, ideal linearity, quick response/recovery and long lifetime in a very wide humidity range at room temperature. 相似文献
7.
Jiaojiao Song Ouyang Wang Huaibin Shen Qingli Lin Zhaohan Li Lei Wang Xintong Zhang Lin Song Li 《Advanced functional materials》2019,29(33)
In the study of hybrid quantum dot light‐emitting diodes (QLEDs), even for state‐of‐the‐art achievement, there still exists a long‐standing charge balance problem, i.e., sufficient electron injection versus inefficient hole injection due to the large valence band offset of quantum dots (QDs) with respect to the adjacent carrier transport layer. Here the dedicated design and synthesis of high luminescence Zn1?x CdxSe/ZnSe/ZnS QDs is reported by precisely controlled shell growth, which have matched energy level with the adjacent hole transport layer in QLEDs. As emitters, such Zn1?xCdxSe‐ based QLEDs exhibit peak external quantum efficiencies (EQE) of up to 30.9%, maximum brightness of over 334 000 cd m?2, very low efficiency roll‐off at high current density (EQE ≈25% @ current density of 150 mA cm?2), and operational lifetime extended to ≈1 800 000 h at 100 cd m?2. These extraordinary performances make this work the best among all solution‐processed QLEDs reported in literature so far by achieving simultaneously high luminescence and balanced charge injection. These major advances are attributed to the combination of an intermediate ZnSe layer with an ultrathin ZnS outer layer as the shell materials and surface modification with 2‐ethylhexane‐1‐thiol, which can dramatically improve hole injection efficiency and thus lead to more balanced charge injection. 相似文献
8.
High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality ZnxCd1‐xS/ZnS Core/Shell Quantum Dots
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Huaibin Shen Xianwei Bai Aqiang Wang Hongzhe Wang Lei Qian Yixing Yang Alexandre Titov Jake Hyvonen Ying Zheng Lin Song Li 《Advanced functional materials》2014,24(16):2367-2373
High‐quality violet‐blue emitting ZnxCd1‐xS/ZnS core/shell quantum dots (QDs) are synthesized by a new method, called “nucleation at low temperature/shell growth at high temperature”. The resulting nearly monodisperse ZnxCd1‐xS/ZnS core/shell QDs have high PL quantum yield (near to 100%), high color purity (FWHM) <25 nm), good color tunability in the violet‐blue optical window from 400 to 470 nm, and good chemical/photochemical stability. More importantly, the new well‐established protocols are easy to apply to large‐scale synthesis; around 37 g ZnxCd1‐xS/ZnS core/shell QDs can be easily synthesized in one batch reaction. Highly efficient deep‐blue quantum dot‐based light‐emitting diodes (QD‐LEDs) are demonstrated by employing the ZnxCd1‐xS/ZnS core/shell QDs as emitters. The bright and efficient QD‐LEDs show a maximum luminance up to 4100 cd m?2, and peak external quantum efficiency (EQE) of 3.8%, corresponding to 1.13 cd A?1 in luminous efficiency. Such high value of the peak EQE can be comparable with OLED technology. These results signify a remarkable progress, not only in the synthesis of high‐quality QDs but also in QD‐LEDs that offer a practicle platform for the realization of QD‐based violet‐blue display and lighting. 相似文献
9.
Shixuan Liu Yong Yu Di Wu Xiao Xu Lin Xie Xiaolian Chao Michel Bosman Stephen J. Pennycook Zupei Yang Jiaqing He 《Advanced functional materials》2021,31(5):2007340
The exploration of n-type PbTe as thermoelectric materials always falls behind its p-type counterpart, mainly due to their quite different electronic band structure. In this work, elemental Sb and Cu2Te are introduced into an n-type base material (PbTe)81-Sb2Te3. The introduction of extra Sb can effectively tune the concentration of electrons; meanwhile, Sb precipitates can also scatter low-energy electrons (negatively contribute to the Seebeck coefficient) thus enhance the overall Seebeck coefficient. The added Cu2Te is found to always co-precipitate with Sb, forming an interesting Sb/CuTe core/shell structure; moreover, the interface between core/shell precipitates and PbTe matrix simultaneously shows coherent lattice and strong strain contrast, beneficial for electron transport but adverse to phonon transport. Eventually, a peak figure of merit ZTmax ≈ 1.6 @ 823K and simultaneously an average ZT ≈ 1.0 (323–823 K) are realized in the (PbTe)81Sb2Te3-0.6Sb-2Cu2Te sample, representing the state of the art for n-type PbTe-based thermoelectric materials. Moreover, for the first time the three existing forms of Cu atoms in Cu2Te alloyed PbTe are unambiguously clarified with aberration-corrected scanning transmission electron microscopy (Cs-STEM). 相似文献
10.
Rong Huang Jie Zhang Fenfen Wei Lin Shi Tao Kong Guosheng Cheng 《Advanced functional materials》2014,24(23):3581-3586
High‐quality single‐crystalline ternary (Sb1‐xBix)2Se3 nanowires (NWs) (x = 0–0.88) are synthesized by chemical vapor deposition. Nanowires with x from 0 to 0.75 are indexed as an orthorhombic structure. With increasing Bi incorporation ratio, (Sb1‐xBix)2Se3 NWs exhibit remarkable photoresponsivities, which originate from growing surface Se vacancies and augmented oxygen chemisorptions. Notably, spectra responsivity and external quantum efficiency of an (Sb0.44Bi0.56)2Se3 NW photodetector reach as high as ≈8261.4 A/W and ≈1.6 × 106 %, respectively. Those excellent performances unambiguously demonstrate that Sb–Bi–Se NWs are promising for the utilizations of high‐sensitivity and high‐speed photodetectors and photoelectronic switches. 相似文献
11.
Benjamin Balke Joachim Barth Michael Schwall Gerhard H. Fecher Claudia Felser 《Journal of Electronic Materials》2011,40(5):702-706
In this report an alternative approach for optimization of the thermoelectric properties of half-Heusler compounds is presented.
The common approaches are partial substitution of elements by elements of nearby groups and substitution with homologs. In
this approach we substitute one element by one neighboring element with fewer valence electrons and by one with more electrons.
The amounts of the substitutions are chosen such that the amount of deficiency and excess electrons are compensated. In the
solid solution TiCox(Ni0.5Fe0.5)1-xSb\hbox{TiCo}_{x}(\hbox{Ni}_{0.5}\hbox{Fe}_{0.5})_{1-x}\hbox{Sb}, Co was substituted equally by Fe and Ni. The aim of the substitution was to improve the figure of merit by a reduction of
the thermal conductivity accompanied by an unchanged high Seebeck coefficient. The solid solution TiCox(Ni0.5Fe0.5)1-xSb\hbox{TiCo}_{x}(\hbox{Ni}_{0.5}\hbox{Fe}_{0.5})_{1-x}\hbox{Sb} was synthesized by arc-melting. The structure of the as-cast samples was analyzed by x-ray diffraction. Rietveld refinements
yielded the C1bC1_b structure type with a small amount of antisite disorder between Co and Sb. The thermoelectric properties of the solid solution
were investigated in the temperature range from 2 K to 400 K. A Seebeck coefficient of -260 mV K-1-260\,\mu\hbox{V\,K}^{-1} at 400 K and a reduction of the thermal conductivity to 3 Wm-1 K-13\,\hbox{Wm}^{-1}\,\hbox{K}^{-1} were measured. The figure of merit was enhanced by a factor of about seven to a value of 0.04 at 400 K for TiCo0.8(Ni0.1Fe0.1)Sb\hbox{TiCo}_{0.8}(\hbox{Ni}_{0.1}\hbox{Fe}_{0.1})\hbox{Sb}. 相似文献
12.
M. Brumer A. Kigel L. Amirav A. Sashchiuk O. Solomesch N. Tessler E. Lifshitz 《Advanced functional materials》2005,15(7):1111-1116
The synthesis of PbSe/PbS and PbSe/PbSexS1–x core/shell nanocrystals (NCs) with luminescence quantum efficiencies of 45–55 % is reported. PbSe/PbS NCs are prepared via a two‐stage process, while the PbSe/PbSexS1–x NCs are formed in a single‐stage procedure. The core/shell NCs exhibit an energy tuning of the exciton transitions, with respect to that of the core NC, that is dependent on the core diameter, shell thickness, and composition. 相似文献
13.
We report on the fabrication, structural characterization, and luminescence properties of ZnSe/Si bi‐coaxial nanowire heterostructures. Uniform ZnSe/Si bi‐coaxial nanowire heterostructures are grown on silicon substrates by the simple one‐step thermal evaporation of ZnSe powder in the presence of hydrogen. Both ZnSe and silicon are single‐crystalline in the bi‐coaxial nanowire heterostructures, and there is a sharp interface along the nanowire axial direction. Furthermore, secondary nanostructures of either ZnSe nanobrushes or a SiOx sheath are also grown on the primary bi‐coaxial nanowires, depending on the ratio of the source materials. The experimental evidence strongly suggests that bi‐coaxial nanowires are formed via a co‐growth mechanism, that is, ZnSe terminates specific surfaces of silicon and leads to anisotropic, one‐dimensional silicon growth, which simultaneously serves as preferential nucleation sites for ZnSe, resulting in the bi‐coaxial nanowire heterostructures. In addition, the optical properties of ZnSe/Si nanowires are investigated using low‐temperature photoluminescence spectroscopy. 相似文献
14.
Pingli Qin Tong Wu Zhengchun Wang Lan Xiao Liang Ma Feihong Ye Lun Xiong Xiangbai Chen Haixia Li Xueli Yu Guojia Fang 《Advanced functional materials》2020,30(12)
The plasmonic characteristic of core–shell nanomaterials can effectively improve exciton‐generation/dissociation and carrier‐transfer/collection. In this work, a new strategy based on core–shell Au@CdS nanospheres is introduced to passivate perovskite grain boundaries (GBs) and the perovskite/hole transport layer interface via an antisolvent process. These core–shell Au@CdS nanoparticles can trigger heterogeneous nucleation of the perovskite precursor for high‐quality perovskite films through the formation of the intermediate Au@CdS–PbI2 adduct, which can lower the valence band maximum of the 2,2,7,7‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)9,9‐spirobifluorene (Spiro‐OMeTAD) for a more favorable energy alignment with the perovskite material. With the help of the localized surface plasmon resonance effect of Au@CdS, holes can easily overcome the barrier at the perovskite/Spiro‐OMeTAD interface (or GBs) through the bridge of the intermediate Au@CdS–PbI2, avoiding the carrier accumulation, and suppress the carrier trap recombination at the Spiro‐OMeTAD/perovskite interface. Consequently, the Au@CdS‐based perovskite solar cell device achieves a high efficiency of over 21%, with excellent stability of ≈90% retention of initial power conversion efficiencies after 45 days storage in dry air. 相似文献
15.
Eunseon Yu Baegmo Son Byungmin Kam Yong Sang Joh Sangjoon Park Won‐Jun Lee Jongwan Jung Seongjae Cho 《ETRI Journal》2019,41(6):829-837
The p‐type nanowire field‐effect transistor (FET) with a SiGe shell channel on a Si core is optimally designed and characterized using in‐depth technology computer‐aided design (TCAD) with quantum models for sub‐10‐nm advanced logic technology. SiGe is adopted as the material for the ultrathin shell channel owing to its two primary merits of high hole mobility and strong Si compatibility. The SiGe shell can effectively confine the hole because of the large valence‐band offset (VBO) between the Si core and the SiGe channel arranged in the radial direction. The proposed device is optimized in terms of the Ge shell channel thickness, Ge fraction in the SiGe channel, and the channel length (Lg) by examining a set of primary DC and AC parameters. The cutoff frequency (fT) and maximum oscillation frequency (fmax) of the proposed device were determined to be 440.0 and 753.9 GHz when Lg is 5 nm, respectively, with an intrinsic delay time (τ) of 3.14 ps. The proposed SiGe‐shell channel p‐type nanowire FET has demonstrated a strong potential for low‐power and high‐speed applications in 10‐nm‐and‐beyond complementary metal‐oxide‐semiconductor (CMOS) technology. 相似文献
16.
High Performance Mg2(Si,Sn) Solid Solutions: a Point Defect Chemistry Approach to Enhancing Thermoelectric Properties
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Guangyu Jiang Jian He Tiejun Zhu Chenguang Fu Xiaohua Liu Lipeng Hu Xinbing Zhao 《Advanced functional materials》2014,24(24):3776-3781
A point defect chemistry approach to improving thermoelectric (TE) properties is introduced, and its effectiveness in the emerging mid‐temperature TE material Mg2(Si,Sn) is demonstrated. The TE properties of Mg2(Si,Sn) are enhanced via the synergistical implementation of three types of point defects, that is, Sb dopants, Mg vacancies, and Mg interstitials in Mg2Si0.4Sn0.6‐xSbx with high Sb content (x > 0.1), and it is found that i) Sb doping at low ratios tunes the carrier concentration while it facilitates the formation of Mg vacancies at high doping ratios (x > 0.1). Mg vacancies act as acceptors and phonon scatters; ii) the concentration of Mg vacancies is effectively controlled by the Sb doping ratio; iii) excess Mg facilitates the formation of Mg interstitials that also tunes the carrier concentration; vi) at the optimal Sb‐doping ratio near x ≈ 0.10 the lattice thermal conductivity is significantly reduced, and a state‐of‐the‐art figure of merit ZT > 1.1 is attained at 750 K in 2 at% Zn doped Mg2Si0.4Sn0.5Sb0.1 specimen. These results demonstrate the significance of point defects in thermoelectrics, and the promise of point defect chemistry as a new approach in optimizing TE properties. 相似文献
17.
Well‐aligned nanocrystalline (nc)‐Si/SiOx composite nanowires have been deposited on various substrates at 120 °C using SiCl4/H2 in a hot‐filament chemical vapor deposition reactor. Structural and compositional analyses reveal that silicon nanocrystals are embedded in the amorphous SiOx nanowires. The nc‐Si/SiOx composite nanowires are transparent in the range 500–900 nm. Photoluminescence spectra of the nc‐Si/SiOx composite nanowires have a broad emission band, ranging from 420 to 525 nm. Water vapor from the chamber wall plays a crucial role in the formation of the well‐aligned nanowires. A possible mechanism for the formation of the composite nanowires is suggested. 相似文献
18.
Novel Type‐II InAs/AlSb Core–Shell Nanowires and Their Enhanced Negative Photocurrent for Efficient Photodetection
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Handong Li Hayfaa Alradhi Zhiming Jin Ezekiel A. Anyebe Ana M. Sanchez Wojcioech M. Linhart Robert Kudrawiec Hehai Fang Zhiming Wang Weida Hu Qiandong Zhuang 《Advanced functional materials》2018,28(8)
The control of optical and transport properties of semiconductor heterostructures is crucial for engineering new nanoscale photonic and electrical devices with diverse functions. Core–shell nanowires are evident examples of how tailoring the structure, i.e., the shell layer, plays a key role in the device performance. However, III–V semiconductors bandgap tuning has not yet been fully explored in nanowires. Here, a novel InAs/AlSb core–shell nanowire heterostructure is reported grown by molecular beam epitaxy and its application for room temperature infrared photodetection. The core–shell nanowires are dislocation‐free with small chemical intermixing at the interfaces. They also exhibit remarkable radiative emission efficiency, which is attributed to efficient surface passivation and quantum confinement induced by the shell. A high‐performance core–shell nanowire phototransistor is also demonstrated with negative photoresponse. In comparison with simple InAs nanowire phototransistor, the core–shell nanowire phototransistor has a dark current two orders of magnitude smaller and a sixfold improvement in photocurrent signal‐to‐noise ratio. The main factors for the improved photodetector performance are the surface passivation, the oxide in the AlSb shell and the type‐II bandgap alignment. The study demonstrates the potential of type‐II core–shell nanowires for the next generation of photodetectors on silicon. 相似文献
19.
Xinbo Yang K. Fujiwara K. Maeda J. Nozawa H. Koizumi S. Uda 《Progress in Photovoltaics: Research and Applications》2014,22(5):574-580
The crystal growth shape (CGS) and equilibrium crystal shape (ECS) of silicon in Si melt are observed using in situ observation. Fully faceted silicon CGSs, which are dominated by the {111} facets, are observed from the {112} and {110} orientation. Silicon CGS in three‐dimensional in Si melt is octahedral in shape, bounded by {111} facets. Silicon ECSs in the melt are obtained by the relaxation from the CGSs and exhibit the {111} facets separated by curved interface. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
20.
Xiaoliang Ren Xianghui Zhang Nishuang Liu Li Wen Longwei Ding Zongwei Ma Jun Su Luying Li Junbo Han Yihua Gao 《Advanced functional materials》2015,25(14):2182-2188
A whole interfacial transition of electrons from conduction bands of n‐type material to the acceptor levels of p‐type material makes the energy band engineering successful. It tunes intrinsic ZnO UV emission to UV‐free and warm white light‐emitting diode (W‐LED) emission with color coordinates around (0.418, 0.429) at the bias of 8–15.5 V. The W‐LED is fabricated based on antimony (Sb) doped p‐ZnO nanowire arrays/Si doped n‐GaN film heterojunction structure through one‐step chemical vapor deposition with quenching process. Element analysis shows that the doping concentration of Sb is ≈1.0%. The I–V test exhibits the formation of p‐type ZnO nanowires, and the temperature‐dependent photoluminescence measurement down to 4.65 K confirms the formation of deep levels and shallow acceptor levels after Sb‐doping. The intrinsic UV emission of ZnO at room temperature is cut off in electroluminescence emission at a bias of 4–15.5 V. The UV‐free and warm W‐LED have great potential application in green lights program, especially in eye‐protected lamp and display since television, computer, smart phone, and mobile digital equipment are widely and heavily used in modern human life, as more than 3000 h per year. 相似文献