第 1 條，共 10 條
標題: Room-temperature direct-bandgap electroluminescence from type-IGeSn/SiGeSn multiple quantum wells for 2 mu m LEDs
作者: Peng, LZ (Peng, Linzhi); Li, XL (Li, Xiuli); Zheng, J (Zheng,Jun); Liu, XQ (Liu, Xiangquan); Li, MM (Li, Mingming); Liu, Z (Liu, Zhi); Xue,CL (Xue, Chunlai); Zuo, YH (Zuo, Yuhua); Cheng, BW (Cheng, Buwen)
來源出版物: JOURNAL OF LUMINESCENCE 卷: 228 文獻號: 117539 DOI: 10.1016/j.jlumin.2020.117539 出版年: DEC 2020
摘要: Two Ge1-xSnx/Si0.1Ge0.85Sn0.05 (x = 7.3% and 8.5%) multi-quantumwells (MQWs) based light emitting diodes (LEDs) were designed and fabricated toachieve efficient light emission in the similar to 2 mu m wavelength band.Electroluminescence (EL) at wavelengths of 1980 nm (0.626 eV) and 2060 nm(0.602 eV) from the MQWs light emitting diodes were observed at roomtemperature. Super-linear dependence between the injected current density andEL intensity illustrates the high band-to-band radiative recombinationefficiency. Theoretical calculations using deformation potentials theory revealthat the type-I band alignment is formed, and correspond well with the quantumconfinement effect of the direct-bandgap transitions of n(1 Gamma)- n(1HH).These results indicate that GeSn/SiGeSn MQW-LEDs is a promising full group-IVsilicon-based light source in the 2 mu m waveband.
入藏號: WOS:000579805300059
ISSN: 0022-2313
eISSN: 1872-7883
第 2 條，共 10 條
標題: Understanding angle-resolved polarized Raman scattering from blackphosphorus at normal and oblique laser incidences
作者: Lin, ML (Lin, Miao-Ling); Leng, YC (Leng, Yu-Chen); Cong, X (Cong,Xin); Meng, D (Meng, Da); Wang, JH (Wang, Jiahong); Li, XL (Li, Xiao-Li); Yu, BL(Yu, Binlu); Liu, XL (Liu, Xue-Lu); Yu, XF (Yu, Xue-Feng); Tan, PH (Tan,Ping-Heng)
來源出版物: SCIENCE BULLETIN 卷: 65 期: 22 頁: 1894-1900 DOI: 10.1016/j.scib.2020.08.008 出版年: NOV 30 2020
摘要: The selection rule for angle-resolved polarized Raman (ARPR)intensity of phonons from standard group-theoretical method in isotropicmaterials would break down in anisotropic layered materials (ALMs) due tobirefringence and linear dichroism effects. The two effects result indepth-dependent polarization and intensity of incident laser and scatteredsignal inside ALMs and thus make a challenge to predict ARPR intensity at anylaser incidence direction. Herein, taking in-plane anisotropic black phosphorusas a prototype, we developed a so-called birefringence-linear-dichroism (BLD)model to quantitatively understand its ARPR intensity at both normal andoblique laser incidences by the same set of real Raman tensors for certainlaser excitation. No fitting parameter is needed, once the birefringence andlinear dichroism effects are considered with the complex refractive indexes. Anapproach was proposed to experimentally determine real Raman tensor and complexrefractive indexes, respectively, from the relative Raman intensity along itsprinciple axes and incident-angle resolved reflectivity by Fresnel's law. Theresults suggest that the previously reported ARPR intensity of ultrathin ALMflakes deposited on a multilayered substrate at normal laser incidence can bealso understood based on the BLD model by considering the depth-dependentpolarization and intensity of incident laser and scattered Raman signal inducedby both birefringence and linear dichroism effects within ALM flakes and theinterference effects in the multilayered structures, which are dependent on theexcitation wavelength, thickness of ALM flakes and dielectric layers of thesubstrate. This work can be generally applicable to any opaque anisotropiccrystals, offering a promising route to predict and manipulate the polarizedbehaviors of related phonons. (C) 2020 Science China Press. Published byElsevier B.V. and Science China Press. All rights reserved.
入藏號: WOS:000581061500011
ISSN: 2095-9273
eISSN: 2095-9281
第 3 條，共 10 條
標題: Frequency-Tunable Broadband Microwave Comb Generation Using anIntegrated Mutually Coupled DFB Laser
作者: Zhao, W (Zhao, Wu); Mao, YF (Mao, Yuanfeng); Li, YB (Li, Yaobin);Chen, GC (Chen, Guangcan); Lu, D (Lu, Dan); Kan, Q (Kan, Qiang); Zhao, LJ(Zhao, Lingjuan)
來源出版物: IEEE PHOTONICS TECHNOLOGY LETTERS 卷: 32 期: 22 頁: 1407-1410 DOI: 10.1109/LPT.2020.3027558 出版年: NOV 15 2020
摘要: A microwave frequency comb (MFC) generator based on an integratedmutually coupled (IMC) distributed feedback (DFB) laser is demonstrated. Theproposed MFC generator is simple and compact, only consisting of an IMC laser,a microwave signal generator, and a photodetector. By adjusting the biascurrents of the three sections of the IMC laser and the modulation parameters,the bandwidth of the MFC can be significantly enhanced compared to the caseadopting a solitary DFB laser. The characteristics of the MFC with the tuningcurrent and the modulation parameters were investigated experimentally todetermine the optimum operating condition. A broadband MFC with 40 GHzbandwidth within a +/- 5 dB amplitude variation was achieved under a modulationfrequency of 2 GHz.
入藏號: WOS:000579421500001
作者識別號:
作者 Web of ScienceResearcherIDORCID 號
Lu, Dan 0000-0001-7811-8250
ISSN: 1041-1135
eISSN: 1941-0174
第 4 條，共 10 條
標題: Electric-field-driven exciton vortices in transition metaldichalcogenide monolayers
作者: Chen, YD (Chen, Yingda); Huang, YW (Huang, Yongwei); Lou, WK (Lou,Wenkai); Cai, YY (Cai, Yongyong); Chang, K (Chang, Kai)
來源出版物: PHYSICAL REVIEW B 卷: 102 期: 16 文獻號: 165413 DOI: 10.1103/PhysRevB.102.165413 出版年: OCT 22 2020
摘要: We predict electric-field-driven exciton vortices in transitionmetal dichalcogenide monolayers in the BoseEinstein condensation regime. TheRashba spin-orbit coupling created by perpendicular electric fields couples thebright and dark excitons, behaves like an emerging SU(2) gauge field forexcitons, and induces spatially asymmetric distribution of exciton density. Wefind the interplay between the dipole-dipole interaction among excitons andRashba spin-orbit coupling leads to the phase transitions containing differentvortices, from a single pair of vortices to numerous satellite vorticesappearing at the edge of the sample. The exciton condensation at the K and K'valleys shows mirror-symmetric patterns composed of exciton vortices rotatingoppositely, which are protected topologically by the winding numbers.
入藏號: WOS:000580883800005
ISSN: 2469-9950
eISSN: 2469-9969
第 5 條，共 10 條
標題: A Benchmark Dataset for RSVP-Based Brain-Computer Interfaces
作者: Zhang, SE (Zhang, Shangen); Wang, YJ (Wang, Yijun); Zhang, LJ(Zhang, Lijian); Gao, XR (Gao, Xiaorong)
來源出版物: FRONTIERS IN NEUROSCIENCE 卷: 14 文獻號: 568000 DOI: 10.3389/fnins.2020.568000 出版年: OCT 2 2020
摘要: This paper reports on a benchmark dataset acquired with abrain-computer interface (BCI) system based on the rapid serial visualpresentation (RSVP) paradigm. The dataset consists of 64-channelelectroencephalogram (EEG) data from 64 healthy subjects (sub1, horizontalellipsis , sub64) while they performed a target image detection task. For eachsubject, the data contained two groups ("A" and "B"). Eachgroup contained two blocks, and each block included 40 trials that correspondedto 40 stimulus sequences. Each sequence contained 100 images presented at 10 Hz(10 images per second). The stimulus images were street-view images of twocategories: target images with human and non-target images without human.Target images were presented randomly in the stimulus sequence with aprobability of 1 similar to 4%. During the stimulus presentation, subjects wereasked to search for the target images and ignore the non-target images in asubjective manner. To keep all original information, the dataset was the rawcontinuous data without any processing. On one hand, the dataset can be used asa benchmark dataset to compare the algorithms for target identification inRSVP-based BCIs. On the other hand, the dataset can be used to design newsystem diagrams and evaluate their BCI performance without collecting any newdata through offline simulation. Furthermore, the dataset also provideshigh-quality data for characterizing and modeling event-related potentials(ERPs) and steady-state visual evoked potentials (SSVEPs) in RSVP-based BCIs.The dataset is freely available from.
入藏號: WOS:000579314800001
PubMed ID: 33122990
eISSN: 1662-453X
第 6 條，共 10 條
標題: Tunable Electromagnetically Induced Transparency-Like Spectrum inLithium Niobate on Insulator Platform With Narrow Linewidth
作者: Yu, WQ (Yu, Wenqi); Dai, SX (Dai, Shuangxing); Zhao, YR (Zhao,Yiru); Zhao, QF (Zhao, Qinfeng); Li, JY (Li, Jinye); Liu, JG (Liu, Jianguo)
來源出版物: IEEE PHOTONICS JOURNAL 卷: 12 期: 5 文獻號: 2700308 DOI: 10.1109/JPHOT.2020.3025626 出版年: OCT 2020
摘要: An all-pass racetrack-resonator-Bragg gratings (APRR-BG) onthin-film lithium niobate on insulator (LNOI) based coupling resonant system isproposed to generate tunable electromagnetically induced transparency(EIT)-like transmission. The structure is a normal all-pass racetrack-resonatorwith two Bragg gratings inscribed within the straight waveguides, whichintroduces two different optical pathways in essence, inducing EIT-likespectrum as a result. We investigate the linewidth, and tunability of theEIT-like spectrum, and manufacturing tolerance of the resonant system byutilising the transfer matrix method. The simulation results indicate anextremely narrow linewidth of several picometers, and a high voltagesensitivity of 0.338 GHz/V@1550 nm, which indicates potential for opticalfilter, optical switching, and sensing of the system.
入藏號: WOS:000579383900003
ISSN: 1943-0655
eISSN: 1943-0647
第 7 條，共 10 條
標題: GaN-Based LEDs Grown on Graphene-Covered SiO2/Si (100) Substrate
作者: Song, WR (Song, Wurui); Ren, F (Ren, Fang); Wang, YY (Wang,Yunyu); Yin, Y (Yin, Yue); Zhang, S (Zhang, Shuo); Shi, B (Shi, Bo); Feng, T(Feng, Tao); Wang, JW (Wang, Jianwei); Liang, M (Liang, Meng); Zhang, YY(Zhang, Yiyun); Wei, TB (Wei, Tongbo); Yan, JC (Yan, Jianchang); Wang, JX(Wang, Junxi); Li, JM (Li, Jinmin); Yi, XY (Yi, Xiaoyan); Liu, ZQ (Liu,Zhiqiang)
來源出版物: CRYSTALS 卷: 10 期: 9 文獻號: 787 DOI: 10.3390/cryst10090787 出版年: SEP 2020
摘要: The growth of nitride on large-size and low-cost amorphoussubstrates has attracted considerable attention for applications in large-scaleoptoelectronic devices. In this paper, we reported the growth of GaN-basedlight-emitting diodes (LEDs) on amorphous SiO(2)substrate with the use ofnanorods and graphene buffer layers by metal organic chemical vapor deposition(MOCVD). The effect of different growth parameters on the morphology andvertical-to-lateral aspect ratio of nanorods was discussed by analyzing growthkinetics. Furthermore, we tuned nanorod coalescence to obtain continuous GaNfilms with a blue-LED structure by adjusting growth conditions. The GaN filmsexhibited a hexagonal wurtzite structure and alignedc-axis orientationdemonstrated by X-ray diffractometer (XRD), Raman, and transmission electronmicroscopy (TEM) results. Finally, five-pair InGaN/GaN multi-quantum-wells(MQWs) were grown. The photoluminescence (PL) showed an intense emission peakat 475 nm, and the current-voltage (I-V) curve shows a rectifying behavior witha turn-on voltage of 5.7 V. This work provides a promising fabrication methodfor the large-area and low-cost GaN-based devices on amorphous substrates andopens up the further possibility of nitride integration with Si (100)complementary metal oxide semiconductor (CMOS) electronics.
入藏號: WOS:000580298000001
ISSN: 2073-4352
第 8 條，共 10 條
標題: Broadband High-Efficiency Grating Couplers for Perfectly VerticalFiber-to-Chip Coupling Enhanced by Fabry-Perot-like Cavity
作者: Zhang, Z (Zhang, Zan); Huang, BJ (Huang, Beiju); Zhang, ZY (Zhang,Zanyun); Cheng, CT (Cheng, Chuantong); Bai, B (Bai, Bing); Gao, TX (Gao,Tianxi); Xu, XB (Xu, Xiaobo); Gu, WP (Gu, Wenping); Zhang, L (Zhang, Lin);Chen, HD (Chen, Hongda)
來源出版物: MICROMACHINES 卷: 11 期: 9 文獻號: 859 DOI: 10.3390/mi11090859 出版年: SEP 2020
摘要: We propose a broadband high-efficiency grating coupler forperfectly vertical fiber-to-chip coupling. The up-reflection is reduced, henceenhanced coupling efficiency is achieved with the help of a Fabry-Perot-likecavity composed of a silicon nitride reflector and the grating itself. With thetheory of the Fabry-Perot cavity, the dimensional parameters of the coupler areinvestigated. With the optimized parameters, up-reflection in the C-band isreduced from 10.6% to 5%, resulting in an enhanced coupling efficiency of80.3%, with a 1-dB bandwidth of 58 nm, which covers the entire C-band. Theminimum feature size of the proposed structure is over 219 nm, which makes ourdesign easy to fabricate through 248 nm deep-UV lithography, and lowers thefabrication cost. The proposed design has potential in efficient andfabrication-tolerant interfacing applications, between off-chip light sourcesand integrated chips that can be mass-produced.
入藏號: WOS:000580330100001
PubMed ID: 32957465
作者識別號:
作者 Web of ScienceResearcherIDORCID 號
Xu, Xiaobo 0000-0002-7776-3415
Zhang, Zan 0000-0001-9331-9114
eISSN: 2072-666X
第 9 條，共 10 條
標題: "Fast" Plasmons Propagating in Graphene PlasmonicWaveguides with Negative Index Metamaterial Claddings
作者: Zhao, ZY (Zhao, Zeyang); Su, SJ (Su, Shaojian); Zhou, HJ (Zhou,Hengjie); Qiu, WB (Qiu, Weibin); Qiu, PP (Qiu, Pingping); Kan, Q (Kan, Qiang)
來源出版物: NANOMATERIALS 卷: 10 期: 9 文獻號: 1637 DOI: 10.3390/nano10091637 出版年: SEP 2020
摘要: We propose the monolayer graphene plasmonic waveguide (MGPW),which is composed of graphene core sandwiched by two graphene metamaterial(GMM) claddings and investigate the properties of plasmonic modes propagatingin the waveguide. The effective refraction index of the GMMs claddings takesnegative (or positive) at the vicinity of the Dirac-like point in the bandstructure. We show that when the effective refraction index of the GMMs ispositive, the plasmons travel forward in the MGPW with a positive groupvelocity (vg > 0, vp > 0). In contrast-for the negative refraction indexGMM claddings-a negative group velocity of the fundamental mode (vg < 0, vp> 0) appears in the proposed waveguide structure when the core is sufficientlynarrow. A forbidden band appears between the negative and positive groupvelocity regions, which is enhanced gradually as the width of the coreincreases. On the other hand, one can overcome this limitation and even makethe forbidden band disappear by increasing the chemical potential differencebetween the nanodisks and the ambient graphene of the GMM claddings. Theproposed structure offers a novel scheme of on-chip electromagnetic field andmay find significant applications in the future high density plasmonicintegrated circuit technique.
入藏號: WOS:000580154400001
PubMed ID: 32825372
作者識別號:
作者 Web of ScienceResearcherIDORCID 號
Su, Shaojian 0000-0003-1375-5309
Zhao, Zeyang 0000-0001-9014-7062
Qiu, Weibin 0000-0001-6234-0711
eISSN: 2079-4991
第 10 條，共 10 條
標題: Effect of Processing Technique Factors on Structure andPhotophysical Properties of Perovskite Absorption Layer by Using Two-StepSpin-Coating Method
作者: Zhou, ZX (Zhou, Zixiao); Zou, XP (Zou, Xiaoping); Zhu, JL (Zhu,Jialin); Cheng, J (Cheng, Jin); Ren, HY (Ren, Haiyan); Chang, CC (Chang,Chuangchuang); Yao, YJ (Yao, Yujun); Chen, D (Chen, Dan); Yu, X (Yu, Xing); Li,GD (Li, Guangdong); Wang, JQ (Wang, Junqi); Liu, BY (Liu, Baoyu)
來源出版物: CRYSTALS 卷: 10 期: 9 文獻號: 761 DOI: 10.3390/cryst10090761 出版年: SEP 2020
摘要: The investigation of crystal growth is crucial for us to improvethe film quality and photophysical properties of CH3NH3PbI3(MAPbI(3)). In thetwo-step spin-coating process, the crystal structure could be modulated bycontrolling the growth conditions of PbI(2)and CH3NH3I (MAI) layers. In thispaper, the PbI(2)layer was treated with annealing under different times. Aliquid-liquid diffusion (LLD) mechanism is proposed to modify the deposition ofMAI precursor solution and enhance the flatness of organic-inorganic hybridperovskite film. Furthermore, the perovskite films are prepared using differentconcentrations of MAI. The evolution process of perovskite structure isobserved by modulating the concentration of MAI. The spin-coating of moderateMAI tends to form high quality MAPbI(3)films with enhanced absorption andcarrier extraction capabilities. The high concentration of MAI would cause theperovskite phase transition, which provides a novel perspective to modulate thestructure of organic-inorganic hybrid perovskite in the two-step spin-coatingprocess, although it deteriorates the device performance.
入藏號: WOS:000580879900001
ISSN: 2073-4352