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Arbitrary Partially Entangled Three-Electron W State Concentration with Controlled-Not Gates
SHENG Yu-Bo, FENG Zhao-Feng, OU-YANG Yang, QU Chang-Cheng, ZHOU Lan
Chin. Phys. Lett. 2014, 31 (05):
050303
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DOI: 10.1088/0256-307X/31/5/050303
We describe an efficient entanglement concentration protocol (ECP) for an arbitrary partially entangled three-electron W state. We show that with the help of two ancillary single electrons, the concentration task can be well completed. This ECP has several advantages: Firstly, we only require one pair of partially entangled states. Secondly, only two single electrons are used during the whole protocol. Thirdly, we do not require all the parties to participate in the whole process, and only two parties are needed to perform the operation. Fourthly, the protocol can be repeated to obtain a high success probability. This ECP may be useful in current quantum computation and quantum communication.
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Effect of Topological Connectivity on Firing Pattern Transitions in Coupled Neurons
LIANG Li-Si, ZHANG Ji-Qian, LIU Le-Zhu, WANG Mao-Sheng, WANG Bing-Hong
Chin. Phys. Lett. 2014, 31 (05):
050502
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DOI: 10.1088/0256-307X/31/5/050502
By using the coupled model of Hindmarsh–Rose neuronal systems, we numerically investigate the effect of topology structures on the firing patterns transition (FPT). A four-cell coupled system with all possible configurations are studied. We select the membrane current Iext as a controllable parameter, and set it to be near the left side for one of the bifurcation points. It is found that to have a response from some external stimuli with the proper amplitude and frequencies, the transition will appear between different firing states only when the cells in the system are coupled with some proper topological structures, which implies the occurrence of FPT induced by the configuration in the coupled system. Similar FPT phenomena could also be observed in a five-cell coupled system. Furthermore, we find that such transition behaviors may have some inherent relevance with the synchronization error and the average connective number among cells in the coupled system for different topology structures. These results suggest that the biological neuron systems may achieve an effective response to the external feeble stimulus by selecting the proper configuration and using the corresponding transition mode.
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Design of Elliptical Reflection Zone Plate for Monochromatization of the Ultrafast Betatron Radiation at Low Energy Band
YANG Zu-Hua, ZHAO Zong-Qing, WEI Lai, ZHANG Qiang-Qiang, QIAN Feng, GU Yu-Qiu, CAO Lei-Feng
Chin. Phys. Lett. 2014, 31 (05):
050701
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DOI: 10.1088/0256-307X/31/5/050701
The elliptical reflection zone plate is a kind of optical element in soft x-ray and x-ray ranges and has focusing and dispersion properties. Compared with a transmission zone plate, the required dispersion orders can be easily separated from zeroth order diffraction. It is fabricated on a bulk substrate and does not have much difficulty in the fabrication process. We design a 1000-zone off-axis elliptical reflection zone plate for the monochromatization of the ultrafast betatron radiation at the low energy band, at the designed wavelength of 2.478 nm (500 eV) which is an important spectral part of the betatron radiation, with high spatial resolution, high spectral resolution. Moreover, we simulate the designed reflection zone plate properties. The simulation results show that the spatial resolutions in the spatial direction and the spectral direction are 6.4 μm and 7.3 μm (full width half maximum), respectively, and the spectral resolution reaches up to 496 for the well aligned point source system, which is in good agreement with the theoretical predictions. In addition, we discuss some factors influencing the spectral and spatial resolution, such as the zone number, zone area and the incidence wavelength. The elliptical reflection zone plate also has potential applications in investigating x-ray fluorescence spectra and other fields.
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Hadronic Decays of the Spin-Singlet Heavy Quarkomium under the Principle of Maximum Conformality
ZHANG Qiong-Lian, WU Xing-Gang, ZHENG Xu-Chang, WANG Sheng-Quan, FU Hai-Bing, FANG Zhen-Yun
Chin. Phys. Lett. 2014, 31 (05):
051202
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DOI: 10.1088/0256-307X/31/5/051202
The principle of maximum conformality (PMC) provides a way to eliminate the conventional renormalization scale ambiguity in a systematic way. By applying the PMC scale setting, all non-conformal terms in a perturbative series are summed into the running coupling, and one obtains a unique, scale-fixed prediction at any finite order. In this study, we make a detailed PMC analysis for the spin-singlet heavy quarkoniums decay (into light hadrons) at the next-to-leading order. After applying the PMC scale setting, the decay widths for all those cases are almost independent of the initial renormalization scales. The PMC scales for ηc and hc decays are below 1 GeV; to achieve a confidential pQCD estimation, we adopt several low-energy running coupling models to carry out the estimation. By taking the MPT model, we obtain Γ(ηc →LH)=25.09+5.52−4.28 MeV,Γ(ηb →LH)=14.34+0.92−0.84 MeV, Γ(hc →LH)=0.54+0.06−0.04 MeV and Γ(hb →LH)=39.89+0.28−0.46 keV, where the errors are calculated by taking mc∈[1.40 GeV, 1.60 GeV] and mb∈[4.50 GeV, 4.70 GeV]. These decay widths agree with the principle of minimum sensitivity estimations, in which the decay widths of ηc,b are also consistent with the measured ones.
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Deuterium Retention in the Co-Deposition Carbon Layers Deposited by Radio-Frequency Magnetron Sputtering in D2 Atmosphere
ZHANG Wei-Yuan, SHI Li-Qun, ZHANG Bin, HU Jian-Sheng
Chin. Phys. Lett. 2014, 31 (05):
052901
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DOI: 10.1088/0256-307X/31/5/052901
Carbon is deposited on C and Si substrates by rf magnetron plasma sputtering in a D2 atmosphere. The deposited layers are examined with ion beam analysis and thermal desorption spectroscopy (TDS). The growth rates of the layers deposited on Si decrease with increasing substrate temperature, while increase significantly with the increase of D2 pressure. Meanwhile, the deuterium concentrations in the layers deposited on the Si substrates decrease from 30% to 2% and from 31% to 1% on the C substrates, respectively, when the substrate temperature varies from 350 K to 900 K. Similarly, the D concentration in the layer on the Si substrates increases from 3.4% to 47%, and from 8% to 35% on the C substrates when the D2 pressure increases from 0.3 Pa to 8.0 Pa. D desorption characterized by TDS is mainly in the forms of D2, HD, HDO, CD4, and C2D4, and a similar release peak occurs at 645 K. The release peak of D2 molecules at 960 K can be attributed to the escaped gas from the thin co-deposited deuterium-rich carbon layer in the form of C–D bonding.
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Polarization and Angular Distribution of L? X-Ray Following Inner-Shell 2p3/2 Photoionization of Magnesium-Like Ions
MA Kun, DONG Chen-Zhong, XIE Lu-You, DING Xiao-Bin, QU Yi-Zhi
Chin. Phys. Lett. 2014, 31 (05):
053201
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DOI: 10.1088/0256-307X/31/5/053201
The inner-shell 2p3/2 photoionization and the subsequent decay of Mg-like Fe14+, Cd36+, W62+ and U80+ ions are studied theoretically within the multiconfiguration Dirac–Fock method and the density matrix theory. Special attention is paid to exploring the influence of the non-dipole terms which arise from the multipole expansion of the electron-photon interaction in the photoionization process. The results show that the non-dipole contribution to the total cross section, the magnetic sublevels cross section of the photoionization process, the degree of linear polarization and angular distribution of the subsequent characteristic x-ray radiation become more important with the increase of photons energy and atomic nuclear Z. Especially for the cross section and the degree of linear polarization, the non-dipole contribution arrives at 50% for U80+ at four time energy threshold units. However, for the angular distribution, the maximum contribution does not exceed 4%, even for U80+ ions.
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Room-Temperature Operation of 2.4 μm InGaAsSb/AlGaAsSb Quantum-Well Laser Diodes with Low-Threshold Current Density
XING Jun-Liang, ZHANG Yu, LIAO Yong-Ping, WANG Juan, XIANG Wei, XU Ying-Qiang, WANG Guo-Wei, REN Zheng-Wei, NIU Zhi-Chuan
Chin. Phys. Lett. 2014, 31 (05):
054204
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DOI: 10.1088/0256-307X/31/5/054204
GaSb-based 2.4 μm InGaAsSb/AlGaAsSb type-I quantum-well laser diode is fabricated. The laser is designed consisting of three In0.35Ga0.65As0.1Sb0.9/Al0.35Ga0.65As0.02Sb0.98 quantum wells with 1% compressive strain located in the central part of an undoped Al0.35Ga0.65As0.02Sb0.98 waveguide layer. The output power of the laser with a 50-μm-wide 1-mm-long cavity is 28 mW, and the threshold current density is 400 A/cm2 under continuous wave operation mode at room temperature.
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Multiband Metamaterial Absorber at Terahertz Frequencies
XU Zong-Cheng, GAO Run-Mei, DING Chun-Feng, ZHANG Ya-Ting, YAO Jian-Quan
Chin. Phys. Lett. 2014, 31 (05):
054205
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DOI: 10.1088/0256-307X/31/5/054205
We propose a multi-band metamaterial absorber operating at terahertz frequencies. The design, characterization, and theoretical calculation of the high performance metamaterial absorber are reported. The multi-band metamaterial absorber consists of two metallic layers separated by a dielectric spacer. Theoretical and simulated results show that the metamaterial absorber has four distinct absorption points at frequencies 0.57 THz, 1.03 THz, 1.44 THz and 1.89 THz, with the absorption rates of 99.9%, 90.3%, 83.0%, 96.1%, respectively. Two single band metamaterial absorbers and a dual band metamaterial absorber on the top layer are designed. Some multi-band absorbers can be designed by virtue of combining some single band absorbers. The multiple-reflection theory is used to explain the absorption mechanism of our investigated structures.
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Suppression of the Resonant Scattering in Imperfect Acoustic Cloaking with a Lossy Medium in ?3
LI Meng-Lei, KIM Seungil
Chin. Phys. Lett. 2014, 31 (05):
054301
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DOI: 10.1088/0256-307X/31/5/054301
It has been realized that resonance frequencies of imperfect acoustic cloaking based on a small perturbation of the transformation acoustics in ?2 are located near Dirichlet eigenvalues of the cloaked region [ Chin. Phys. Lett. 26 (2009) 014301; 29 (2012) 124301]. In this work, we study the performance of the three-dimensional approximate cloaking system based on the transformation acoustics and show that the cloaking effect may be deteriorated at zeroth order Neumann eigenvalues of the concealed region. In particular, transmitted fields into the concealed region can be extremely resonated at frequencies corresponding to the zeroth-order Neumann eigenvalues while scattered fields are suppressed well for any frequency. To enhance the cloaking effect at resonance frequencies, we introduce a lossy medium inside the cloaked region and show that the new proposal can reduce the intensity of transmitted fields significantly due to the lossy medium.
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Novel Image Optimization Method for Joint Photoacoustic Tomography
LI Wen-Chao, YUAN Jie, SHEN Qing-Hong, YU Yao, ZHOU Yu, DU Si-Dan, LIU Xiao-Jun, XU Guan, WANG Xue-Ding
Chin. Phys. Lett. 2014, 31 (05):
054302
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DOI: 10.1088/0256-307X/31/5/054302
The distribution of speed of sound (SOS) in biomedical tissue and delay compensation (DC) have significant impact on the image quality of photoacoustic tomography (PAT). When imaging human peripheral joints, using fixed SOS and DC can only ensure that the reconstructed images are focused in a limited depth range, whereas they are defocused at other depths, which cause severe artifacts and blurring. In this work, a linear-DC based reconstruction approach is proposed to focus the whole PAT image region. It is proved by two in vivo experiments that, compared with traditional delay-and-sum back projection algorithms, the proposed method can effectively optimize the image quality of articular tissues in PAT.
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Fast Electron Spatial Temperature Distribution Studied by X-Ray 2D Imaging
TIAN Ye, WANG Wen-Tao, XIA Chang-Quan, WANG Cheng, XU Yi, LI Wen-Tao, QI Rong, ZHANG Zhi-Jun, LIANG Hong, YU Chang-Hai, LENG Yu-Xin, LIU Jian-Sheng
Chin. Phys. Lett. 2014, 31 (05):
055201
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DOI: 10.1088/0256-307X/31/5/055201
We present the experimental and numerical results of two-dimensional x-ray imaging due to fast electron transport in a solid target. A 40-μm-thick copper film target is irradiated by a 100 mJ, 50 fs normal incident laser pulse. The full width at half maximum of the x-ray photon dose is 25 μm, and the divergence angle of fast electrons is 25°–30°, which is detected by the pin-hole x-ray imaging technique. The target surface plasma layer is compressed by a ponderomotive force into a depth of 0.2λ. The plasma wave accompanied by fast electrons transporting into the target is studied by dividing the plasma into layers in a radial direction. A narrow fast electron channel, which is approximately 8 μm–10 μm in width, mainly contributes to the x-ray dose.
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Synthesis and Photoluminescence Properties of GaAs Nanowires Grown on Fused Quartz Substrates
ZHAO Yu-Feng, LI Xin-Hua, SHI Tong-Fei, WANG Wen-Bo, ZHOU Bu-Kang, DUAN Hua-Hua, ZENG Xue-Song, LI Ning, WANG Yu-Qi
Chin. Phys. Lett. 2014, 31 (05):
056101
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DOI: 10.1088/0256-307X/31/5/056101
GaAs nanowires are synthesized on fused quartz substrates by using molecular beam epitaxy via a vapor-liquid-solid mechanism with gold as the catalyst. High resolution-transmission electron microscopy is used to probe crystal quality and growth direction. Micro-photoluminescence measurements are carried out to examine the optical properties of GaAs NWs. The low-temperature photoluminescence (PL) emission of nanowires (NWs) has a peak at 1.513 eV, 2 meV lower than the zinc blende GaAs free exciton energy. The temperature-dependent band gap of NWs is seen to be somewhat different from that observed in bulk GaAs, and the PL rapidly quenches above 150 K, with an activation energy of 6.3 meV reflecting the presence of the longitudinal twins' structure.
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The Near Surface Morphology of P3HT:PCBM Blend Films Studied by Near-Edge X-Ray Absorption Fine Structure
ZENG Xue-Song, SHI Tong-Fei, YE Chang-Hui, LI Ning, LI Xin-Hua, WANG Yu-Qi
Chin. Phys. Lett. 2014, 31 (05):
056102
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DOI: 10.1088/0256-307X/31/5/056102
The microstructure of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) blends with various annealing temperatures are investigated in detail by the near-edge x-ray absorption fine structure. Under higher annealing temperature (Tanneal≥160°C), P3HT shows an unusual fluidity and aggregation in the surface. After annealing, the enrichment polymer component recrystallizes and forms a single P3HT phase layer in the surface of blend films. Moreover, it gives direct evidence of the PCBM content diffusing to the near surface of blend films during annealing treatment. These findings are beneficial to improving the morphology of polymer/fullerene blend films.
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Effect of Stress in GaN/AlInGaN Grown on GaN Templates with Different Stress States
FENG Xiang-Xu, LIU Nai-Xin, ZHANG Ning, WEI Tong-Bo, WANG Jun-Xi, LI Jin-Min
Chin. Phys. Lett. 2014, 31 (05):
056801
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DOI: 10.1088/0256-307X/31/5/056801
We clarify the effect of the stress in GaN templates on the subsequent AlInGaN deposition by simply growing 150 nm AlInGaN on a 30 μm GaN template (sample 1) prepared by hydride vapor phase epitaxy and a 2.3 μm thin control GaN template (sample 2) prepared by metalorganic chemical vapor deposition. X-ray diffraction and secondary iron mass spectroscopy measurements reveal the stress states (tensile stress and full relaxed for samples 1 and 2, respectively) and compositions (Al0.169In0.01 Ga0.821N, Al0.171In0.006Ga0.823N for samples 1 and 2, respectively) of AlInGaN. By carefully eliminating other possible factor, as template surface roughness, it is concluded that different stress states of AlInGaN should stem from different stress states of GaN templates.
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Synthesis and Growth Mechanism: A Novel Fishing Rod-Shaped GaN Nanorods
ZHANG Shi-Ying, XIU Xiang-Qian, HUA Xue-Mei, XIE Zi-Li, LIU Bin, CHEN Peng, HAN Ping, LU Hai, ZHANG Rong, ZHENG You-Dou
Chin. Phys. Lett. 2014, 31 (05):
056802
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DOI: 10.1088/0256-307X/31/5/056802
A novel fishing rod-shaped GaN nanorod is successfully fabricated through a new method by using the two-step growth technology. This growth method is applicable to continuous synthesis and is able to produce a large number of single-crystalline GaN nanorods with a relatively high purity and at a low cost. X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy are used to characterize the as-synthesized nanorods. The results show that most of the nanorods consist of a main rod and a top curved thread. It is single-crystal GaN with hexagonal wurtzite structure. The representative photoluminescence spectrum at room temperature exhibits a strong UV light emission band centered at 370.8 nm. Furthermore, a possible two-stage growth mechanism of the fishing rod-shaped GaN nanorod is also briefly discussed.
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A Numerical Method for Modeling the Effects of Irregular Shape on Interconnect Resistance
CHEN Bao-Jun, TANG Zhen-An, JU Yan-Jie
Chin. Phys. Lett. 2014, 31 (05):
057102
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DOI: 10.1088/0256-307X/31/5/057102
When clock frequencies exceed gigahertz, the skin depth in analog and digital circuits greatly decreases. The irregular shape of the cross section of the interconnect plays an increasingly important role in interconnect parasitic extraction. However, existing methods only focus on the rough surface of the interconnect, while ignoring other irregular shapes, such as the trapezoidal cross section. In this work, a new simulation method is proposed for irregular interconnects, which is applicable to arbitrary irregular shapes and to a wide range of frequencies. The method involves generating a mesh information file firstly, and then extracting the frequency-dependent resistance based on a numerical solution of scalar wave modeling by using the method of moments. The singularity extraction method is used to calculate the self-inductors. The data from experiments verify the accuracy of our proposed method.
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Fano Resonance by Symmetry Breaking Stub in a Metal-Dielectric-Metal Waveguide
TANG Dong-Hua, DING Wei-Qiang
Chin. Phys. Lett. 2014, 31 (05):
057301
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DOI: 10.1088/0256-307X/31/5/057301
The coupling of a stub obliquely intersected with a metal-dielectric-metal plasmonic waveguide is investigated by using the finite difference in time domain method. Results show that an odd mode, except for the usual even mode, is excited in the stub due to the symmetry breaking of the oblique intersection. Moreover, the results show that the quality factor of the odd mode is very high in comparison with that of the usual even mode, which is then explained by the symmetry breaking of the oblique stub intersection. The superposition of the even and the odd mode generates a Fano shaped spectrum with a very narrow linewidth. The effect of metallic loss and compensation are also discussed. Both the stub and the waveguide are compact in size, and simple in structure, which are beneficial for the achievements of narrow band filtering, sensing, lasing, and nonlinearity enhancement.
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Forward Current Transport Mechanisms of Ni/Au–InAlN/AlN/GaN Schottky Diodes
WANG Xiao-Feng, SHAO Zhen-Guang, CHEN Dun-Jun, LU Hai, ZHANG Rong, ZHENG You-Dou
Chin. Phys. Lett. 2014, 31 (05):
057303
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DOI: 10.1088/0256-307X/31/5/057303
We fabricate two Ni/Au-In0.17Al0.83N/AlN/GaN Schottky diodes on substrates of sapphire and Si, respectively, and investigate their forward-bias current transport mechanisms by temperature-dependent current-voltage measurements. In the temperature range of 300–485 K, the Schottky barrier heights (SBHs) calculated by using the conventional thermionic-emission (TE) model are strongly positively dependent on temperature, which is in contrast to the negative-temperature-dependent characteristic of traditional semiconductor Schottky diodes. By fitting the forward-bias I–V characteristics using different current transport models, we find that the tunneling current model can describe generally the I–V behaviors in the entire measured range of temperature. Under the high forward bias, the traditional TE mechanism also gives a good fit to the measured I–V data, and the actual barrier heights calculated according to the fitting TE curve are 1.434 and 1.413 eV at 300 K for InAlN/AlN/GaN Schottky diodes on Si and the sapphire substrate, respectively, and the barrier height shows a slightly negative temperature coefficient. In addition, a formula is given to estimate SBHs of Ni/Au–InAlN/AlN/GaN Schottky diodes taking the Fermi-level pinning effect into account.
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Manipulation of Surface Plasmon Polaritons by Phase Modulation of Source Field with Inverse Problem Algorithm
LIU Chun-Xiang, LIANG Guo-Tao, ZHANG Mei-Na, LI Zhen-Hua, CHENG Chuan-Fu
Chin. Phys. Lett. 2014, 31 (05):
057306
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DOI: 10.1088/0256-307X/31/5/057306
The predetermined field distributions can be achieved by phase modulation of the source field to manipulate the propagation of surface plasmon polaritons (SPPs). The modulations of the radius of the circular slit are according to the phase distributions on the slit, which are calculated by using the Gerchberg–Saxton algorithm with the known field. We design the surface geometric shape of the radius-varied circular slit for exciting the SPP field with the linear, triangular, square and circular distribution characteristics, respectively. The slit structure designed for the circular field distribution is a plasmonic vortex lens that can be used to generate the vortex with the specified size of the primary ring, which shows that this heuristic method has the potential to devise plasmonic devices.
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Role of Oxygen Vacancy Arrangement on the Formation of a Conductive Filament in a ZnO Thin Film
ZHAO Jing, DONG Jing-Yu, ZHAO Xu, CHEN Wei
Chin. Phys. Lett. 2014, 31 (05):
057307
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DOI: 10.1088/0256-307X/31/5/057307
We perform first-principles calculations for ZnO thin films with oxygen vacancy defects. The densities of states, partial atomic densities of states, charge density differences and atomic populations are presented. We show that the SET process, i.e., from a high resistive state to a low resistive state, is attributable to the aggregation and regular arrangement of the oxygen vacancies, which causes the formation of conductive filaments and leads to the low resistive state of the system.
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Electrically Pumped Ultraviolet Random Lasing from p-ZnO:As Based on p-ZnO/N-GaN Heterojunction
ZHANG Yuan-Tao, XIA Xiao-Chuan, WU Bin, SHI Zhi-Feng, YANG Fan, YANG Xiao-Tian, ZHANG Bao-Lin, DU Guo-Tong
Chin. Phys. Lett. 2014, 31 (05):
058101
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DOI: 10.1088/0256-307X/31/5/058101
p-ZnO:As is prepared by the GaAs interlayer doping method. The potential applications of p-ZnO:As are evaluated by applying it into the construction of a p-ZnO/n-GaN heterojunction, though its hall, electrochemical capacitance-voltage and photoluminescence results show a hole concentration at the level of ~1017 cm?3 and a good optical quality. Ultraviolet random lasing is detected from the studied device under forward bias. Specific lasing modes are confirmed to originate from p-ZnO:As by further introducing the p-ZnO/MgO/n-GaN heterostructure. The resulting random lasing phenomena demonstrate the promising prospects in device application of p-ZnO:As fabricated by using our methods.
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A Silicon-Based Positive-Intrinsic-Negative Photodetector Double Linear Array on a Thick Intrinsic Epitaxial Layer
YUAN Li, WU Can, ZHANG Zhao-Hua, REN Tian-Ling
Chin. Phys. Lett. 2014, 31 (05):
058502
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DOI: 10.1088/0256-307X/31/5/058502
To measure small particles in clouds without the optical amplification system, a new type of p-i-n photodetector linear array with 128 diode units altogether is designed and realized. In each die, there are two rows of photodiode line array, and each row has 64 photodiodes. Every photodiode has a size of 100 μm × 100 μm with an individual output, and each of them is isolated by the trenches. The depth of them has the same thickness as that of the epitaxial layer, which is designed to be 30 μm to guarantee sufficient absorption of photons and leave a margin for the diffusion of p-type and n-type region. The detector has been tested with a laser whose wavelength was 650 nm and irradiance is 50 mW/cm2. The achieved photocurrent is 2 μA. Hence, the current responsivity is about 0.4 A/W, and the external quantum efficiency is 76.45%. The dark current is less than 600 pA. Both of the sufficient absorption of photons and low dark current are achieved by utilizing the thick epitaxial intrinsic layer. Low interference of adjacent photodiodes is also guaranteed by the trenches around the photodiodes. With the obtained performance, the photodetector can be used to measure the diameter of precipitation particles in clouds. Therefore, rainfall can be judged based on the diameter of particles.
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Germanium PMOSFETs with Low-Temperature Si2H6 Passivation Featuring High Hole Mobility and Superior Negative Bias Temperature Instability
WANG Hong-Juan, HAN Gen-Quan, LIU Yan, YAN Jing, ZHANG Chun-Fu, ZHANG Jin-Cheng, HAO Yue
Chin. Phys. Lett. 2014, 31 (05):
058503
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DOI: 10.1088/0256-307X/31/5/058503
We investigate negative bias temperature instability (NBTI) on high performance Ge p?channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) with low-temperature Si2H6 passivation. The Ge pMOSFETs exhibit an effective hole mobility of 311 cm2/V?s at an inversion charge density of 2.5×1012 cm?2. NBTI characterization is performed to investigate the linear transconductance (GM, lin) degradation and threshold voltage shift (ΔVTH) under NBT stress. Ge pMOSFETs with a 10 yr lifetime at an operating voltage of -0.72 V are demonstrated. The impact of the Si2H6 passivation temperature is studied. As the passivation temperature increases from 350°C to 550°C, the degradation of NBTI characteristics, e.g., GM, lin loss, ΔVTH and an operating voltage for a lifetime of 10 yr, is observed.
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48 articles
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