检索结果-南通市图书馆

Journal of University of Science and Technology Beijing 2007年第3期14卷 266-270页

作者： Hongyu Liu Xueming Ma Dongmei Jiang wangzhou shi College of Science Wuhan University of Science and Technology Wuhan 430081 China Department of Physics East China Normal University Shanghai 200062 China

Y2O3-doped ZnO-based varistor ceramics were prepared using high-energy ball milling （HEBM） and low-temperature sin- tering technique, with voltage-gradient of 1934-2197 V/mm, non-linear coefficients of 20.8-21.8, leakage currents of 0.59-1.04 μA, and densities of 5.46-5.57 g/cm3. With increasing Y2O3 content, the voltage-gradient increases because of the decrease of ZnO grain size; the non-linear coefficient and the leakage current improve but the density decreases because of more porosity; the donor con- centration and density of interface states decrease, whereas the barrier height and width increase because of the acceptor effect of Y2O3 in varistor ceramics.

关键词： inorganic materials electrical properties high-energy ball milling varistor microstructure low-temperature sintering zinc oxide yttrium oxide

Tunable 2H–TaSe_2 room-temperature terahertz photodetector

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第4期28卷 18-22页

作者： Jin Wang Cheng Guo Wanlong Guo Lin Wang wangzhou shi Xiaoshuang Chen Department of Physics Shanghai Normal University State Key Laboratory for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

Two-dimensional transition metal dichalcogenides(TMDs) provide fertile ground to study the interplay between dimensionality and electronic properties because they exhibit a variety of electronic phases, such as semiconducting, superconducting, charge density waves(CDW) states, and other unconventional physical properties. Compared with other classical TMDs, such as Mott insulator 1T–TaS_2 or superconducting 2H–NbSe_2, bulk 2H–TaSe_2 has been a canonical system and a touchstone for modeling the CDW measurement with a less complex phase diagram. In contrast to ordinary semiconductors that have only single-particle excitations, CDW can have collective excitation and carry current in a collective fashion. However, manipulating this collective condensation of these intriguing systems for device applications has not been explored. Here, the CDW-induced collective driven of non-equilibrium carriers in a field-effect transistor has been demonstrated for the sensitive photodetection at the highly-pursuit terahertz band. We show that the 2H–TaSe_2-based photodetector exhibits a fast photoresponse, as short as 14 μs, and a responsivity of over 27 V/W at room temperature. The fast response time, relative high responsivity and ease of fabrication of these devices yields a new prospect of exploring CDW condensate in TMDs with the aim of overcoming the existing limitations for a variety of practical applications at THz spectral range.

关键词： terahertz detection transition metal dichalcogenides photoconductive

A polarization-sensitive,self-powered,broadband and fast Ti_(3)C_(2)T_(x)MXene photodetector from visible to near-infrared driven by photogalvanic effects

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2022年第5期17卷 9-15页

作者： Bo Liu Liyu Qian Yanliang Zhao Yiwen Zhang Feng Liu Yi Zhang Yiqun Xie wangzhou shi Department of Physics Shanghai Normal UniversityShanghai 200234China

Broadband,self-power,and polarization-sensitivity are desirable qualities for a ***,currently few photodetectors can fulfill these requirements ***,we propose a Ti_(3)C_(2)T_(x)(MXene)photodetector that is driven by the photogalvanic effect with impressive performances.A polarization-sensitive photocurrent is generated at zero bias under the illumination of linearly polarized laser light of 1064 nm,with an extinction ratio of ***,a fast response with a 32/28 ms rise/decay time and a large on/off switching ratio of 120 are ***,a robust zero-bias photocurrent is also generated in the photodetector under the illumination of 940 and 620 nm light,as well as the white light,showing a broadband photoresponse from the near-infrared to ***,quantum transport simulations indicate that the photogalvanic effect plays an important role in the generation of the polarized photocurrent at zero bias due to the broken space inversion symmetry of the stacked few-layer Ti_(3)C_(2)T_(x).Our results shed light on a potential application of the Ti_(3)C_(2)T_(x)–MXene in the low-power photodetection with high performances.

关键词： photodetection polarization-sensitivity photogalvanic effects Ti_(3)C_(2)T_(x) MXene quantum transport simulations

Hall Effect of an Oriented Superconducting YBa_(2)Cu_(3)O_(y) Film

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1991年第10期8卷 541-543页

作者： HE Zhenhui SHA Jian WANG Shunxi CHENG Xiang'ai ZHOU Guien ZHANG Qirui shi wangzhou YAO Weiguo QI Zhenzhong Department of Physics and*Structure Research LaboratoryUniversity of Science and Technology of ChinaHefei 230026 Department of Physics Zhejiang Universityj Hangzhou 310027 Department of Physics Zhongshan UniversityGuangzhou 510275 Institute of Solid State Physics Academia SinicaHefei 230031

A superconducting YBa_(2)Cu_(3)O_(y) thin film,which is well oriented at(001)direction and in which no grain boundary is observed in the resolution limit of scanning electron microscope micrograph,is selected for the Hall effect measurement from 80 to 220 K under a magnetic field of 3 T.A very narrow and negative peak of the Hall voltage(V_(H))is found in the superconducting£nuisition region.A linear dependence of the carrier concentration fnjjJ on temperature is found in the normal *** appearance of such a negative peak is attributed to the intrinsic anisotropy of the Hall coefficient(Rn)related to the direction of the applied field and current.

关键词： grain narrow attributed

氧含量对a-SiO_xN_y薄膜荧光特性的影响

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

光谱学与光谱分析 2000年第4期20卷 569-571页

作者：黄翀石旺舟汕头大学物理系汕头515063

采用PECVD方法制备了a SiOxNy 薄膜 ,观察到强荧光发射现象 ,荧光光谱由波段范围为 2 60～3 5 0nm和 5 0 0～ 70 0nm的宽谱带和位置分别为 3 65、 3 75、 3 80、 73 5和 74 5nm的荧光发射峰组成。通过改变沉积过程中氢分压研究了氧含量... 详细信息

采用PECVD方法制备了a SiOxNy 薄膜 ,观察到强荧光发射现象 ,荧光光谱由波段范围为 2 60～3 5 0nm和 5 0 0～ 70 0nm的宽谱带和位置分别为 3 65、 3 75、 3 80、 73 5和 74 5nm的荧光发射峰组成。通过改变沉积过程中氢分压研究了氧含量及荧光特性的影响 ,随着氢分压下降 ,薄膜中氧含量升高 ,荧光峰强度增加 ,但位置不变 ;而荧光带在强度增加的同时 ,中心位置产生红移。根据实验结果对荧光起源及变化机制进行了讨论。

关键词： a-SiOxNy薄膜氧含量荧光光谱 PECVD 制备

Effects of cooling rate on the microstructure and electrical properties of Dy_2O_3-doped ZnO-based varistor ceramics

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2007年第1期26卷 39-44页

作者： LIU Hongyu KONG Hui JIANG Dongmei shi wangzhou MA Xueming ZHANG Huining Department of Physics East China Normal University Shanghai 200062 China College of Science Wuhan University of Science and Technology Wuhan 430081 China Shanghai Research Institute of Petrochemical Technology Shanghai 201208 China

The microstructure, electrical properties, and density of Dy2O3-doped ZnO-based varistor ceramics, prepared using high-energy ball milling （HEBM） and sintered at 800℃, were investigated by increasing the cooling rate in the order of H （slow cooling in furnace） → L （cooling in furnace） → K （cooling in air）. With the increase in cooling rate, the grain size and density decreased, the breakdown voltage （VImA/mm） increased, and the nonlinear coefficient （α） and leakage current （IL） exhibited extremum. The sample with the cooling type L showed the best properties with the breakdown voltage of 2650 V/ram, o：of 20.3, IL of 5.2 laA, and density of 5.42 g/cm^3. The barrier height （ФB）, donor concentration （Nd）, density of the interface states （Nd）, and barrier width （ω） all exhibited extremum during the alteration in cooling rate. The different relative amount of Bi-rich phase and its distribution as well as the characteristic parameters of grain boundary, resulting from the alteration of cooling rate, led to the changes in the properties of varistor ceramics.

关键词： varistor ZnO Dy2O3 microstructure electrical properties high-energy ball milling low-temperature sintering

Room-temperature nitrogen-rich niobium nitride photodetector for terahertz detection

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2024年第11期20卷 641-646页

作者： LU Xuehui LIU Binding CHI Chengzhu LIU Feng shi wangzhou Department of Physics Mathematics&Science CollegeShanghai Normal UniversityShanghai 200234China

A sensitive room-temperature metal-semiconductor-metal(MSM)structure is fabricated on high-resistivity silicon substrates(ρ>4000 Ω·cm)for terahertz(THz)detection by utilizing the photoconductive *** radiation is absorbed by the nitrogen-rich niobium nitride,the number of free electrons and electrical conductivity *** detector without an attached antenna boasts a voltage responsivity of 7058 V/W at a frequency of 310 GHz as well as small noise density of 3.5 nV/Hz^(0.5) for a noise equivalent power of about 0.5 pW/Hz^(0.5).The device fabricated by the standard silicon processing technology has large potential in high-sensitivity THz remote sensing,communication,and materials detection.

关键词： antenna noise utilizing

以SiF_4+H_2为气源PECVD法低温制备多晶硅薄膜

在线全文

学校读者我要写书评

暂无评论

太阳能学报 2004年第3期25卷 333-336页

作者：邱春文石旺舟黄翀汕头大学物理系汕头515063

采用常规的PECVD法在低温(≤400℃)条件下制得大颗粒(直径>100nm)、高迁移率(～20cm2/vs),择优取向(220)明显的多晶硅薄膜。选用的反应气体为SiH4和H2混合气体。加入少量的SiH4后,沉积速率提高了将近10倍。通过本实验,我们认为在低温时... 详细信息

采用常规的PECVD法在低温(≤400℃)条件下制得大颗粒(直径>100nm)、高迁移率(～20cm2/vs),择优取向(220)明显的多晶硅薄膜。选用的反应气体为SiH4和H2混合气体。加入少量的SiH4后,沉积速率提高了将近10倍。通过本实验,我们认为在低温时促使多晶硅结构形成的反应基元应是SiFmHn(m+n≤3),而不可能是SiHn(n≤3)基团。

关键词：多晶硅薄膜瞰 Ⅷ法低温制备

CaCu_3Ti_4O_(12)陶瓷在太赫兹频段的介电特性研究

在线全文

学校读者我要写书评

暂无评论

光学学报 2015年第5期35卷 279-284页

作者：代秀松赵振宇何晓勇石旺舟上海师范大学物理系上海200234

针对太赫兹（1 THz=1012Hz）电容器件发展的需求,研究了呈现巨介电和不呈现巨介电两种状态Ca Cu3Ti4O12（CCTO）陶瓷在THz波段的介电响应特性。在微波波段,小颗粒（Φ〈2μm）CCTO的介电常数εr〈700,无巨介电特征,而大颗粒（Φ〉10μm... 详细信息

针对太赫兹（1 THz=1012Hz）电容器件发展的需求,研究了呈现巨介电和不呈现巨介电两种状态Ca Cu3Ti4O12（CCTO）陶瓷在THz波段的介电响应特性。在微波波段,小颗粒（Φ〈2μm）CCTO的介电常数εr〈700,无巨介电特征,而大颗粒（Φ〉10μm）CCTO的εr〉2000,呈现巨介电特征;两组CCTO陶瓷的介电损耗值Tanδ在0.1~0.6之间。然而,在THz波段,两种颗粒度CCTO的介电常数几乎完全相等（εr=72±3）,且损耗不超过0.18。实验结果表明,CCTO陶瓷组分的离子极化率主导了在THz波段的介电常数εr,而大颗粒CCTO对THz电磁波的散射超过小颗粒CCTO,导致介电损耗值Tanδ上升。因此,在THz波段,降低CCTO颗粒大小不会影响介电常数,反而能够降低介电损耗。这一结果表明CCTO陶瓷是制备THz波段电容的理想介电材料。

关键词：材料太赫兹光谱学频谱特性散射

SiH_4射频放电功率耗散机制的光发射研究

在线全文

学校读者我要写书评

暂无评论

功能材料 2000年第2期31卷 144-145页

作者：石旺舟黄羽中姚若河林揆训林璇英汕头大学非晶半导体实验室广东汕头515063

采用OMA - 4 0 0 0测量了SiH4射频辉光放电等离子体的光发射谱 ,研究了其谱线强度随放电射频功率和反应气体流量间的变化关系。发现在放电射频功率增加和反应气体流量升高的过程中 ,其等离子体状态分别发生性质不同的转变 ,这种转变联... 详细信息

采用OMA - 4 0 0 0测量了SiH4射频辉光放电等离子体的光发射谱 ,研究了其谱线强度随放电射频功率和反应气体流量间的变化关系。发现在放电射频功率增加和反应气体流量升高的过程中 ,其等离子体状态分别发生性质不同的转变 ,这种转变联系到射频功率耗散机制的变化。当反应气体流量增加时 ,电子获得能量的机制由阴极暗区加速转变为等离子体内电场的加热效应 ;而在放电功率升高的过程中 ,离子轰击阴极产生二次电子发射效应导致了光发射谱强度急剧增强的转变。

关键词： SiH4 射频辉光放电功率耗散光发射谱