吴锦雷
目前从事纳米薄膜、纳米线、纳米电子器件的研究。
个性化签名
- 姓名:吴锦雷
- 目前身份:
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学术头衔:
博士生导师,
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学科领域:
材料科学基础学科
- 研究兴趣:目前从事纳米薄膜、纳米线、纳米电子器件的研究。
吴锦雷, 男, 1943年12月生。1967年毕业于清华大学无线电电子学系,1981年在北京大学无线电电子学系获得我国首批硕士学位。1992年被破格评为教授, 1994年被评为博士生导师。所在一级学科是电子科学与技术,二级学科是物理电子学。他担任国家核心学术刊物“真空科学与技术学报”(EI等收录)的主编。他在从事超短激光脉冲检测用的纳米信息功能薄膜的研究中, 提出了激光功率密度临界阈值测试方法, 发现了新型纳米光电薄膜在激光作用下多光子光电发射灵敏度上升的特殊现象。他深入进行全新型光电转换纳米薄膜材料超快光电时间响应特性的研究, 首次得到这类薄膜的超快光学瞬态弛豫, 发现了纳米微粒复合薄膜在飞秒激光脉冲作用下相干声子振荡现象,他成功地解释了复合介质薄膜飞秒超快时间响应的实验结果,并首次给出了埋藏于半导体基质中的金纳米微粒中电子声子相互作用的常数,揭示了自然科学规律。这些研究成果有非常好的应用背景,在国际同行学者中也引起极大兴趣。他承担多项国家级和省部级重大科研项目,国家自然科学基金重大项目子课题负责人,教育部科技研究重点项目负责人。是多项国家自然科学基金项目负责人。目前从事纳米薄膜、纳米线、纳米电子器件的研究。承担国家重点基础研究发展规划(973项目)子课题负责人。1977年12月获辽宁省阜新市科学技术成果奖。1993年中国科学院自然科学二等奖获得者,2000年北京市科技进步三等奖第一获奖人。获准了多项国家发明专利。1999年出版科技专著和教材2本。发表学术论文一百多篇,多次被他人引用。
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成果数
14
【期刊论文】Study of optical transient relaxation of an Ag-O-Ba thin film
吴锦雷, J.L. Wu a, *, C.M. Wang a, Q.D.Wu a, Z.J. Xia b, Y.H. Zou b
Thin Solid Films 281-282(1996)249-251,-0001,():
-1年11月30日
Under the action of laser pulses with a wavelength of 647nm and a pulse duration of 150fs, the optical transient response of an Ag-O-Ba thin film was obtained by the pump-probe method. Optical relaxation is a process in which non-equilibrium electrons, excited by laser pulses and originating from metallic ultrafine particles, retum fo the equilibrium state. The optical transient relaxation of an Ag-O-Ba thin film consists of fast and stow parts. The fast part occurs in 200 fs and is caused by non-equilibrium electrons entering the matrix. The slow part occurs in 1.6ps and is caused by non-equilibrium electrons scattering within the lattice and interface between the Ag ultrafine particles and the matrix.
Optical transient relaxation, Thin film, Ultrafine particle
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吴锦雷, J.L. Wu*, C.M. Wang
Solid-State Electronics 43(1999)1755-1761,-0001,():
-1年11月30日
Under the stimulation of laser pulses with a wavelength of 647 nm and a pulse duration of 150 fs, the optical transient response of Ag-BaO thin film was obtained by the pump-probe method. Optical relaxation is a process in which nonequilibrium electrons, excited by laser pulses and originating from Ag nano-scale particles, return to the equilibrium state. Its optical transient relaxation consists of a faster part and a slower one. The faster part is only 200 fs and is caused by nonequilibrium electrons entering the matrix. The slower part is 1.6ps and is caused by nonequilibrium electrons scattering with the lattice and the interface between the Ag nano-scale particles and the matrix. From calculated results, the theoretical curve was coincident with experimental one. The thin film containing Ag nano-scale particles embedded in BaO semiconductor matrix has extremely fast photoelectron response time.
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【期刊论文】A new internal field-assisted photocathode based on Ag-O-Cs composite thin films
吴锦雷, Q.F. Zhang, W.M. Liu, Z.Q. Xue, J.L. Wu*
Solid State Communications 122(2002)515-518,-0001,():
-1年11月30日
Internal field-assisted Ag-O-Cs photocathode with sandwich-like structure was successfully fabricated by depositing a silver electrode on the surface of Ag-O-Cs composite thin films that were pre-grown onto a conductive glass substrate. Enhanced photoemission was observed from Ag-O-Cs composite thin films when an internal assistant electric field was applied to the photocathode through the designed sandwich-like structure. The total increase of photoelectronic quantum yield corresponding to the applied 30V bias was about 15.7% while the photocathode was irradiated by the light with wavelength of 510nm. Theoretical analysis indicates that such an enhanced photoemission can be attributed to the field-induced variations in the energy-band structure of Ag-O-Cs thin films, including both the decrease of interfacial barrier between the embedded Ag nanoparticles and the CsxO (2≤x<3) semiconductor matrix and the degradation of the vacuum level at the surface.
A., Thin films, A., Nanoparticles, D., Electronic band structure, D., Internal field-assisted photoemission
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【期刊论文】End potential barriers of single-walled carbon nanotubes and their role in field emission
吴锦雷, Ji Luo, L.-M. Peng, Z.Q. Xue, and J.L. Wu*
PHYSICAL REVIEW B 66, 155407 (2002),-0001,():
-1年11月30日
Very short single-walled carbon nanotube (SWNT) models carrying a net negative charge are employed to simulate tube tips in field emission situations and then, density-functional theory calculations are carried out on these models to obtain their potential barrier shapes and electric-field distributions. These results, incorporated with the SWNT band structures, are used to analyze field emission properties of SWNTs. It is shown that theoretically, low applied voltage (about ten and several volts) might generate emission current as large as 100 nanoamperes from a single SWNT, and closed end geometries lead to a better emission effect, due to their higher electron energy. In addition, limitations of the adopted theoretical approach are discussed, along with its possible improvement.
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【期刊论文】Density-functional-theory calculations of charged single-walled carbon nanotubes
吴锦雷, Ji Luo, L.-M. Peng, Z.Q. Xue, and J.L. Wu*
PHYSICAL REVIEW B 66, 115415 (2002),-0001,():
-1年11月30日
The electronic structures of charged carbon nanotube cluster models were calculated with the densityfunctional-theory (DFT) method. With the increasing number of extra electrons, (a) a potential barrier is formed near the tube wall; its height increases and the width at the highest occupied molecular-orbital (HOMO) level decreases; (b) the HOMO energy increases linearly, giving chances to electrons to tunnel through the barrier and escape; (c) the total energy first decreases and then increases, presenting a perfect parabolic curve and indicating an optimum number of extra electrons; and (d) electrical field near the tube was worked out. A comparison between the tube and a perfect conductor demonstrates some of their resemblances, but the exact properties such as the tube capacitance depend on the quantum theory calculations. The totalenergy variation obeys Koopmans' theorem and although calculated with DFT method, it can be expressed in terms of the tube's classical parameters such as capacitance and work function. The electronic charge rearrangement after the addition of extra electrons is presented and this might be the determinant of the electronic structures of charged carbon nanotubes.
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吴锦雷, J.L. Wu*, G.M. Zhang, W.M. Liu, Q.F. Zhang, Q.D. Wu
Physica B 307(2001)9-14,-0001,():
-1年11月30日
The Ag-BaO thin films are a new kind of photoemissive thin films, which have transient optical and ultrafast photoelectronic response. The properties of the Ag-BaO thin films establish the application foundation of detecting ultrashort infrared laser pulses. The measurement of the quantum yield of photoemission for ultrashort laser pulses is different from that for normal visible light. The experimental results present that the quantum yield of Ag-BaO thin films is of the order of magnitude of 10-6 under the action of a single laser pulse when the incident infrared laser wavelength is 1.06μm. It is two orders of magnitude higher than that of pure metals at the same conditions. The quantum yield under the action of a single-chain laser pulse, which comprises 11 single pulses of duration 40ps separated by 10ns, increases rapidly following increasing incident energy of the laser. In this case, the Ag-BaO thin films present multiphoton emission of 2-photon process and higher quantum yield of 10-5.
Photoemission, Quantum yield, Thin film, Ultrashort infrared laser pulse
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【期刊论文】Calculations of adsorption of O2 and H2O on a carbon nanotube tip in field-emission conditions
吴锦雷, Ji Luo, Z X Zhang, L-M Peng, Z Q Xue and J L Wu
J. Phys. D: Appl. Phys. 36(2003)3034-3038,-0001,():
-1年11月30日
In this paper, density-functional-theory calculations show that O2 and H2O behave differently when they are adsorbed on a single-walled carbon nanotube (SWNT) tip, especially if the tip carries a net negative charge as in the field-emission situation. H2O molecules can be adsorbed on both closed and open-ended SWNTs, and the extra negative charge strengthens the adsorption. O2 molecules can be adsorbed on a closed SWNT, but they are desorbed when an extra negative charge is present. Quite differently, O2 molecules are decomposed and chemisorbed on an open-ended zigzag SWNT, even if an extra negative charge exists. Furthermore, the adsorbed O2 and H2O molecules affect the potential distribution of the SWNT tip differently, leading to their different effects on the field-emission properties of SWNTs.
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吴锦雷, Qifeng Zhang, Danling Wang, Qihuang Gong and JinleiWu,
J. Phys. D: Appl. Phys. 35(2002)1326-1329,-0001,():
-1年11月30日
Optical transient absorption spectra of Ag-BaO thin film were detected in the wavelength range from 450 to 800nm by the pump supercontinuum-probe technique with 130 fs time resolution. The optical ultrafast relaxation, in which the electrons near the Fermi level of silver nanoparticles were excited to non-equilibrium state and then returned to equilibrium state, was observed. The decay times were exponentially fitted and varied from 4 to 0.67ps depending on the probe wavelength. The peak unoccupied state, X'4, of electrons in silver was estimated to locate at 1.47eV above the Fermi level.
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【期刊论文】Positive electron affinity of fullerenes: Its effect and origin
吴锦雷, Ji Luo, L.-M. Peng, Z.Q. Xue and J.L. Wu a)
J. Chem. Phys., Vol. 120, No.17, 1 May 2004,-0001,():
-1年11月30日
The universal variation pattern of the total energy of various fullerenes including single-walled carbon nanotubes with respect to their extra charge is revealed by the density-functional-theory calculations. The parabolic energy-charge curve with its lowest energy value corresponding to a negatively charged fullerene indicates that these carbon materials have positive electron affinity and are not in the most stable state. The positive electron affinity seems to originate from the π-electrons and is found to be related to the aggregation property of fullerenes.
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【期刊论文】Enhanced photoemission of Ag-O-Cs composite thin films with an internal electric field
吴锦雷, Q.F. Zhang, W.M. Liu, Z.Q. Xue and J.L. Wu a)
J. Appl. Phys., Vol. 89, No.4, 15 February 2001,-0001,():
-1年11月30日
Ag-O-Cs thin films with internal field-assisted structure were fabricated, and enhanced photoemission was observed when the internal electric field was applied to the thin films. The increase of photoelectronic quantum yield, corresponding to the applied 30V bias, was about 15.7%, while the thin films were irradiated by the light with wavelength of 510nm. From an analysis of the electric potential distribution in the Ag-O-Cs thin films with the applied internal electric field, it is found that the interfacial barrier between the Ag nanoparticles and the Cs2O matrix is decreased and the vacuum level at the surface is degraded. The calculated barrier curves for various applied biases are illustrated to show the thinning effect of internal electric field on the interfacial barrier width. The theoretical lowering of interfacial barrier height is obtained as 0.08 and 0.22eV when the thin films are stimulated by applied bias of 1 and 30V, respectively. Further, a group of formulas as well, based upon the electric potential distribution in the Ag-O-Cs thin films, is deduced to describe the relationship between the applied bias and the degradation of the surface vacuum level. The enhanced photoemission of Ag-O-Cs thin films is attributed to the field-induced variations in the energy band structure which are considered to result in the increased probabilities for the photoexcited electrons to travel through the interfacial barrier and escape into the vacuum.
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