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Jiangjiang Feng Xiaohui Li Tianci Feng Yamin Wang Jie Liu Han Zhang 《Annalen der Physik》2020,532(1):1900437
MXenes, as a legendary family of 2D van der Waals nanosheets materials, are extensively studied due to their unique characteristics of broadband nonlinear optical response. In particular, MXenes have excellent nonlinear optical properties of very large nonlinear absorption coefficients and very large nonlinear refractive indexes, which have attracted people's great attentions to study the application of MXenes in photonics, electronics, and optoelectronics in recent years. However, the high-repetition-rate (HRR) ultrafast pulses are not explored based on these kinds of materials. MXene Ti3C2Tx saturable absorber (SA) based on micro-fiber is fabricated by optical deposition method. Here, MXene Ti3C2Tx SA is used to achieve 36th harmonic mode-locking with a repetition rate of 218.4 MHz, a central wavelength of 1566.9 nm, the pulse width of 850 fs, and the spectral width of 3.51 nm. The maximum average output power and pulse energy are 6.95 mW and 0.032 nJ, respectively. This research based on MXene Ti3C2Tx light modulator opens a bright avenue for advanced nonlinear photonics. 相似文献
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随着石墨烯材料的发现,二维材料被人们广泛认识并逐渐应用,相比于传统二维材料,二维过渡金属碳化物(MXene)的力学、磁学和电学性能更加优异.本文分别利用HF溶液和LiF/HCl溶液刻蚀Ti3AlC2获得了Ti3C2Tx样品,通过电子扫描显微镜(SEM)、X射线光电子能谱(XPS)和气敏特性分析,研究了刻蚀剂对Ti3C2Tx材料结构和气敏性能的影响.材料结构分析表明:HF和LiF/HCl刻蚀剂均对Ti3C2Tx材料具有良好的刻蚀效果;气敏性能结果表明:LiF/HCl刻蚀剂制备的Ti3C2Tx的气敏性能优于HF刻蚀剂,并实现了室温下宽范围、较高灵敏和较高稳定地检测NH3.分析认为:LiF/HCl溶液刻蚀制备的Ti3C2T<... 相似文献
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《Laser u0026amp; Photonics Reviews》2018,12(2)
Studies of the nonlinear optical phenomena that describe the light‐matter interactions in 2D crystalline materials have promoted a diverse range of photonic applications. MXene, as a recently developed new 2D material, has attracted considerable attention because of its graphene‐like but highly tunable and tailorable electronic/optical properties. In this study, we systematically characterize the nonlinear optical response of MXene Ti3C2Tx nanosheets over the spectral range of 800 nm to 1800 nm. A large effective nonlinear absorption coefficient (βeff∼‐10−21 m2/V2) due to saturable absorption is observed for all of the testing wavelengths. The contribution of saturable absorption is two orders of magnitude higher than other lossy nonlinear absorption processes, and the amplitude of βeff strongly depends on the light bleaching level. A negative nonlinear refractive index (n2∼‐10−20 m2/W) with value comparable to that of the intensively studied graphene was demonstrated for the first time. These results demonstrate the efficient broadband light signal manipulating capabilities of Ti3C2Tx, which is only one member of the large MXene family. The capability of an efficient broadband optical switch is strongly confirmed using Ti3C2Tx as saturable absorbers for mode‐locking operation at 1066 nm and 1555 nm, respectively. A highly stable femtosecond laser with pulse duration as short as 159 fs in the telecommunication window is readily obtained. Considering the diversity of the MXene family, this study may open a new avenue to advanced photonic devices. 相似文献
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Mingxing Chen Xinpeng Jiang Jie Huang Junbo Yang Jiagui Wu Yiming Liang Tianwu Wang Peiguang Yan 《Advanced Optical Materials》2024,12(4):2301694
Ti3C2Tx materials have been developed to have application space in many fields, but there are not many works that can be compatible with infrared (IR) stealth and electromagnetic interference (EMI) shielding at the same time. To realize the multiband high EMI shielding of Ti3C2Tx materials, and to achieve stealth effect in the IR band, in this work, a composite textile is prepared by combining the Ti3C2Tx material with a carbon cloth and sputtering a very thin gold film on the surface. This composite textile can realize high EMI shielding compatible with IR stealth, in which the EMI shielding efficiency for microwave Xa-band (8GHza-12.4GHz) is up to 71.8 dB, for microwave Kaa-band (26.5GHza-40GHz) is up to 75.02 dB, and for terahertza-band is about 30 dB. IR emissivity is as low as 0.1, and the lowest emissivity under a certain temperature reaches 0.07, which can withstand a high temperature of 500 °C. In addition, this composite textile has flexible and bendable wear. The thickness of the whole textile is about 400 µm, of which the Ti3C2Tx material thickness is only about 10 µm, the thinnest reaches 2 µm. Such a textile can be used in both people's livelihood and military applications, which has far-reaching significance. 相似文献
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The photogalvanic effect (PGE) occurring in noncentrosymmetric materials enables the generation of a dc photocurrent at zero bias with a high polarization sensitivity, which makes it very attractive in photodetection. However, the magnitude of the PGE photocurrent is usually small, leading to a low photoresponsivity, and therefore hampers its practical application in photodetection. Here, we propose an approach to largely enhancing the PGE photocurrent by applying an inhomogenous mechanical stretch, based on quantum transport simulations. We model a two-dimensional photodetector consisting of the wide-bandgap MgCl2/ZnBr2 vertical van der Waals heterojunction with the noncentrosymmetric C3v symmetry. Polarization-sensitive PGE photocurrent is generated under the vertical illumination of linearly polarized light. By applying inhomogenous mechanical stretch on the lattice, the photocurrent can be largely increased by up to 3 orders of magnitude due to the significantly increased device asymmetry. Our results propose an effective way to enhance the PGE by inhomogenous mechanical strain, showing the potential of the MgCl2/ZnBr2 vertical heterojunction in the low-power UV photodetection. 相似文献
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H. Schneider S. Ehret C. Schönbein K. Schwarz G. Bihlmann J. Fleissner G. Tränkle G. Böhm 《Superlattices and Microstructures》1998,23(6):1289-1295
We have investigated the influence of the final states of bound-to-continuum transitions within the conduction band of asymmetric quantum well structures on the photocurrent. This influence manifests itself by an energy-dependent oscillation of the current direction. We observe pronounced oscillations at zero bias voltage in a double quantum well structure, induced by an asymmetric excitation into continuum states with positive and negative momentum, i.e. by a photogalvanic effect (PGE). If this effect is superimposed on an asymmetric backrelaxation, similar oscillations are observed in the spectrum when the latter asymmetry is compensated by an external electric field. Theoretically, we find a strong relation between the PGE and a quantum interference effect occurring in the continuum. 相似文献
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Jean Besbas Karan Banerjee Jaesung Son Yi Wang Yang Wu Matthew Brahlek Nikesh Koirala Jisoo Moon Seongshik Oh Hyunsoo Yang 《Advanced Optical Materials》2016,4(10):1642-1650
Topological insulators (TIs) form a new class of materials with an insulating bulk and conducting surfaces ensured by topologically protected surface states (TPSS). The impact of the helicity of a normally incident laser beam on the photovoltaic effect in the TI Bi2Se3 is investigated. The observation of a helicity‐dependent photovoltaic effect for normally incident light indicates the presence of out‐of‐plane spin components for some TPSSs due to the hexagonal warping. In addition, fluctuations in the electrostatic potential at the surface locally break the rotational symmetry of the film allowing the helicity‐dependent photovoltaic effect. Our result suggests that engineering local electrostatic potentials in Bi2Se3 would allow the control of optically generated spin currents, which may be useful for applications in spin‐optoelectronics. 相似文献
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汞是一种有毒的重金属,在生产生活中以各种形式排放的汞对生态及人类健康都存在一定程度的威胁.因此,寻找高效的汞吸附剂具有十分重要的意义.本文基于密度泛函理论的第一性原理计算方法,研究了汞在Ti2NO2(MXene)和具有一个氧空位缺陷的Ti2NO2(Ov-Ti2NO2)上的吸附和氧化机理.计算结果表明Hg0在Ti2NO2表面的吸附为物理吸附,在Ov-Ti2NO2表面为化学吸附. Ti2NO2表面氧空位的存在可以改善HgO与Ov-Ti2NO2之间的相互作用,从而使吸附能提高116 kJ/mol. Hg0在Ov-Ti2NO2表面氧化为HgO的反应能垒为92.55 kJ/mol,小于其在Ti2<... 相似文献
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Taoyu Zou Xiyuan Liu Renzheng Qiu Ya Wang Shuyi Huang Chuan Liu Qing Dai Hang Zhou 《Advanced Optical Materials》2019,7(11)
Organometal halide perovskites have been considered as promising candidates for high‐performance low‐cost photodetectors. Nonetheless, as perovskite photodetectors are usually built on glass or polymer substrates, their UV‐C (200–280 nm) photodetection ability is quite limited due to the high absorption of glass or polymer substrates. Here, a uniform UV photodetector array which integrates perovskite photodiodes with inorganic CsPbBr3 quantum dot (QD) fluorophor is reported. CsPbBr3 quantum dot fluorophor not only acts as an efficient down‐conversion layer to convert UV light into 510 nm light, but also functions as a protective layer to prevent degradation of hybrid organic–inorganic perovskite by UV light. Compared to direct UV‐C (279 nm) detection with perovskite photodiode, the QD integrated photodetector shows a higher responsibility and detectivity to UV‐C, with values enhanced by 1 order in magnitude. This work provides a low‐cost and effective approach for all perovskite‐based UV‐C photodetectors and imagers. 相似文献
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Transition metal carbides and nitrides (MXene) quantum dots (QDs) are potentially important for versatile applications, including ultra-narrow photonics. Here, a simple method for controlling the sizes and solution concentrations of Ti2C-MXene-QDs are shown, and then their optical properties are systematically investigated and compared. The nonlinear optical characteristics of QDs can be adjusted through the QD size and solution concentration. QDs with smaller sizes of 1–3 nm have stronger absorptivity, larger modulation depth and lower nonsaturable loss, and QDs with higher concentrations have stronger absorptivity and larger modulation depth but higher nonsaturable loss. These QDs are further applied to construct loop-cavity ultranarrow lasers whose narrowest laser linewidth is 624.5 Hz, highest signal-to-noise ratio (SNR) is 77.63 dB and lowest power fluctuation is 0.4%. A comparison of these indicators indicates that smaller and more homogeneous MXene QD solutions with proper concentrations favor ultra-narrow photonics. The laser power is also amplified to ≈60 mW by an erbium-doped fiber amplifier (EDFA). 相似文献
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本文利用分子动力学模拟方法, 研究了非晶态Ti3Al合金在300 K时的短程序和中程序。利用对相关函数分布函数、配位数和Voronoi多面体方法研究了微观局域结构短程序和中程序。 研究发现：在Ti3Al合金非晶体中,短、中程序具有二十面体或缺陷二十面体的壳层结构。 相似文献
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Jie Zhang Zixu Sa Pengsheng Li Zhongjun Zhai Fengjing Liu Mingxu Wang Guangcan Wang Yanxue Yin Yang Li Wenxiang Mu Zhitai Jia Feng Chen Zai-xing Yang 《Advanced Optical Materials》2024,12(13):2302665
The persistent photocurrent (PPC) and high carrier concentration are challenging the ultraviolet photodetection behaviors of amorphous InGaO films. Herein, InGaO/PbI2 heterojunction is constructed by an all-solution synthesis process to set up a built-in electric field at the heterojunction interface, which is aimed at the inhibition of PPC, suppression of dark current, and promotion of photogenerated carrier separation. With an optimized In content of 90%, the as-fabricated InGaO/PbI2 heterojunction photodetector exhibits excellent self-powered near-ultraviolet photodetection behaviors with high Ilight/Idark ratio of 104, ultralow dark current of 10−13 A and fast response times of 0.8/0.6 ms. Additionally, benefiting to the all-solution synthesis process and amorphous characteristic, InGaO/PbI2 heterojunction can be implanted onto any useful substrates to achieve the specific function of photodetection. The as-fabricated InGaO/PbI2 heterojunction flexible self-powered photodetector exhibits outstanding mechanical flexibility, bending endurance, and photoelectric stability. When the InGaO/PbI2 heterojunction is implanted onto the transparent substrate, it demonstrates excellent omnidirectional self-powdered photodetection performance and imaging capability. All results promise all-solution-processed InGaO for next-generation advanced optoelectronics. 相似文献
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David K. Ferry 《Superlattices and Microstructures》2000,28(5-6)
The connection between the minimum size of an electron wavepacket, and the introduction of an effective potential is discussed. The effective potential approach has a long history of use in trying to transition the gap between classical mechanics and quantum mechanics. An effective potential is one in which the quasi-classical regime is approximated through a density which arises from the effective potential W(x) through exp[ − βW(x)]. The generation of the effective potentialW (x) gives the effects of the onset of quantization in the system. In this paper, we study the use of the effective potential in a triangular well formed between the oxide and the depletion field of the semiconductor. We determine the quantization energy of the carriers in the potential well and their mean set-back from the interface. Finally, we show the connection between the effective potential and the Bohm-derived quantum potentials that have become of interest in simulations. 相似文献
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We have calculated the differential conductance of metallic carbon nanotubes by the scatter matrix methon.It is found that the differential conductance of metallic nanotube-based devices oscillates as a function of the bias voltage between the two leads and the gate voltage.Oscillation period T is directly proportional to the reciprocal of nanotube length.In addition,we found that electronic transport properties are sensitive to variation of the length of the nanotube. 相似文献
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