首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 281 毫秒
1.
基于高温超导单晶材料Bi2Sr2CaCu2O8+x(BSCCO)的约瑟夫森(Josephson)本征结器件制备工艺,成功制备出形貌整齐、特性良好、一致性高的大尺寸太赫兹辐射源本征结器件.从工艺的各个步骤出发,总结了要点,并对原有工艺做出改进.通过扫描电子显微镜观察刻蚀形貌,总结了光刻最佳后烘温度条件,提出了一套重复性好、成功率高的工艺方法.  相似文献   

2.
耐熔微掩膜法制备高温超导Josephson结   总被引:1,自引:0,他引:1  
在超导Josephson结的制备过程中,传统的成结方式为对超导薄膜进行化学刻蚀或离子刻蚀,以形成特定图形的结.而刻蚀这一步常常会给结的性能带来负面影响,从而直接导致超导器件性能的下降.本介绍了一种利用耐融微掩模制备高温超导Josephson结的方法.本方法的特点是:一次成结无需后期刻蚀,利用此方法可以避免刻蚀工艺对超导器件性能的影响,制备高质量的高温超导Josephson结.本给出利用此方法制备高温超导YBCO/YSZ双晶结的有关工艺,以及初步的实验结果.  相似文献   

3.
本征Josephson结的表面结的特性研究   总被引:2,自引:0,他引:2  
在用Bi2Sr2CaCu2O8 δ(BSCCO)单晶制备本征结时,最上面的Cu-O层由于受到所沉积的金属层的影响,其超导性能将发生退化,从而使得表面上两个邻近的Cu-O层形成的表面结具有不同于内部本征结的性质.我们对表面结的I~V、Ic'~T、R~T等电运输特性进行了分析和研究,发现表面结的临界温度Tc通常都比较低,而且临界电流随温度的变化关系也不同于正常本征结.并且利用旁路电阻的方法,成功观察到了被旁路后表面结的ac Josephson效应.  相似文献   

4.
采用光刻蚀和Ar离子刻蚀技术成功地在Bi-2212单晶表面制备出台阶型本征Josephson单个结,并在5~65K范围内用四引线法测量了该结零场下的I~V特征曲线.结果表明,临界电流几乎保持不变,但返回电流随温度增加而增大;与此同时,Mccumber参数βc随着温度增加而减小.临界温度附近,跳跃电压ΔV明显偏离BCS理论.  相似文献   

5.
高温超导Josephson结混频器的分析研究   总被引:4,自引:0,他引:4  
利用高温超导Josephson结已经实现了毫米波、亚毫米波波段的谐波混频.我们通过对高温超导颗粒晶界结、双晶结、内禀结的制备和混频实验对比研究,分析比较了其I-V曲线特性及其在液氮制冷下的混频结果.  相似文献   

6.
大尺寸的Josephson结放置于Q值足够高的谐振腔中,当其Josephson频率ω=2cV_c/h激励起腔的第r个本征模谐振时,这个振荡将反馈辐照结,必须考虑反馈场本征模的空间部分在结上是不同的。理论上得到了和文献[2]不同的结果,给出了阶跃电流随磁场的变化,分析了腔的反馈场本征模和Josephson结的辐射电磁波空间匹配的条件,解释了为什么大尺寸的Josephson结不存在周期小于φ_0的阶梯效应的物理原因。  相似文献   

7.
采用预先在衬底上刻蚀出台阶然后原位外延生长高 T_c 超导薄膜的工艺,制备了高 T_c 台阶结 Josephson 器件.文中研究了直流 Josephson 电流对温度和外加微波功率的关系,实验结果与磁通流器件的行为基本相符.  相似文献   

8.
采用光刻蚀和Ar离子刻蚀技术成功地在Bi-2212单晶表面制备出台阶型本征Josephson单个结,并在5-65K范围内用四引线法测量了该结零场下的Ⅰ~Ⅴ特征曲线.结果表明,临界电流几乎保持不变,但返回电流随温度增加而增大;与此同时,Mccumber参数βc随着温度增加而减小.临界温度附近,跳跃电压△V明显偏离BCS理论.  相似文献   

9.
超导Josephson隧道结是实现超导量子比特的基本元件.本文介绍了一种利用电子束曝光技术和电子束斜蒸发技术相结合的方法来制备铝超导Josephson隧道结.这种方法工艺简单,通过一次光刻就可完成;而且可以通过调节下层光刻胶厚度、斜蒸发角度、悬空桥区宽度等参数可以有效地控制隧道结的面积大小;此外,本方法通过采用不对称电极结构有效地改善了隧道结的漏电流特性,满足了制备超导量子比特的要求.  相似文献   

10.
大尺寸的Josephson结放置于Q值足够高的谐振腔中,当其Josephson频率ω=2cV0/h激励起腔的第r个本征模谐振时,这个振荡将反馈辐照结,必须考虑反馈场本征模的空间部分在结上是不同的。理论上得到了和文献[2]不同的结果,给出了阶跃电流随磁场的变化,分析了腔的反馈场本征模和Josephson结的辐射电磁波空间匹配的条件,解释了为什么大尺寸的Josephson结不存在周期小于φ0的阶梯效应的物理原因。 关键词:  相似文献   

11.
气相外延ZnSe单晶膜的自由激子发光   总被引:1,自引:1,他引:0  
张家骅  张吉英 《发光学报》1989,10(4):265-270
本文在77K和N2激光器3371谱线高密度激发的VPE ZnSe单晶膜上,首次得到了起因于自由激子与自由激子(Ex-Ex)散射的发光谱带(P带),理论拟合了该谱带的形状并讨论了它的发光特性。文中把在选择的VPE ZnSe外延单晶膜中得到P带的起因归结为这些ZnSe外延单晶膜的质量较高。  相似文献   

12.
本文测量了在77K和正向脉冲电流密度为50~500mA/mm2的激发下,ZnSe MIS二极管的电致发光光谱.首次在高电流密度激发下的ZnSe晶体的电致发光光谱上,观测到自由激子与自由激子间(Ex-Ex)的散射.本中根据自由激子的动能分布,讨论了2LO声子协助的自由激子伴线的形状,发现当激发电流密度增高时,自由激子的有效温度大于晶格温度,这可归结为激子与激子间的非弹性散射.  相似文献   

13.
During the fabrication of intrinsic Josephson junctions (IJJs) with Bi2Sr2CaCu2O8+δ (BSCCO) single crystals, the superconductivity of the surface Cu-O layer is degraded because of a deposited metal film on top of the stack. Thus, the characteristics of the surface junction consisting of the surface Cu-O double layers remarkably differ from those of the junctions deep in the stack, which will be referred to as ordinary IJJs. The electrical transport characteristics of the surface junction, such as I-V, I c′-T, and R-T, show that the critical temperature T c′ of the surface junction is always lower than that of ordinary IJJs, and that the change of its critical current I c′ with temperature is different from that of ordinary IIJs. Furthermore, by shunting the surface junction resistively, we are able to observe the AC Josephson effect at 3-mm waveband. Translated from Chinese Journal of Low Temperature Physics, 2005, 27(2) (in Chinese)  相似文献   

14.
Recently, Wang et al. proposed a three-party simultaneous quantum secure direct communication (3P-SQSDC) scheme with EPR pairs, which enables three involved parties to exchange their secret messages simultaneously by using an EPR pair. This work proposed an enhancement on Wang et al.'s scheme. With the enhancement, the communications in the improved 3P-SQSDC can be paralleled and thus improves the protocol efficiency.  相似文献   

15.
Whispering gallery modes (WGMs), due to their high quality factors, small mode volumes and simple fabrications, have potential applications especially in sensing. In this work, we theoretically propose a mass sensor based on a realistic cavity optomechanical system (such as in Weis et al., Science 330, 1520 [2010]) in the presence of a strong pump laser and a weak probe laser. The mass of external bioparticles (such as smallpox virus and influenza virus) landing onto WGM cavity can be detected accurately via the probe transmission spectrum. Furthermore, based on this scheme one can even determine a single virus mass via monitoring the half-linewidth of the probe transmission spectrum. Through detecting the virus mass, one may identify the kinds of different viruses.  相似文献   

16.
Recent work has shown that site-controlled dots (QD) grown on (1 1 1)B GaAs substrates, pre-patterned with tetrahedral pyramidal recesses (Baier et al., 2006) [1], (Pelucchi et al., 2007) [2], (Zhu et al., 2007) [3] are suitable for the generation of single and entangled photons (Young et al., 2009) [4]. We recently introduced InGaAs/GaAs site controlled QD structures which demonstrated record breaking spectral purity, and we showed that increasing the indium concentration of the active region allows easy tunability of the emission wavelength (Mereni et al., 2009) [5], [6]. We present here the first theoretical analysis of the emission energies and optical properties of this system as a function of QD height and In concentration. We model the dots using an 8 band k.p theory chosen to provide the best convergence and performance for structures oriented specifically along the (1 1 1) crystallographic direction.  相似文献   

17.
In the present work we deal with the scattering dispersion and attenuation of elastic waves in different types of nonhomogeneous media. The iterative effective medium approximation based on a single scattering consideration, for the estimation of wave dispersion and attenuation, proposed in Tsinopoulos et al., [Adv. Compos. Lett. 9, 193-200 (2000)] is examined herein not only for solid components but for liquid suspensions as well. The iterations are conducted by means of the classical relation of Waterman and Truell, while the self-consistent condition proposed by Kim et al. [J. Acoust. Soc. Am. 97, 1380-1388 (1995)] is used for the convergence of the iterative procedure. The single scattering problem is solved using the Ying and Truell formulation, which with a minor modification can accommodate the solution of scattering on inclusions in liquid. Theoretical results for several different systems of particulates and suspensions are presented being in excellent agreement with experimental data taken from the literature.  相似文献   

18.
In a previous work El et al. (2006) [1] exact stable oblique soliton solutions were revealed in two-dimensional nonlinear Schrödinger flow. In this work we show that single soliton solution can be expressed within the Hirota bilinear formalism. An attempt to build two-soliton solutions shows that the system is “close” to integrability provided that the angle between the solitons is small and/or we are in the hypersonic limit.  相似文献   

19.
单个囚禁离子的Jaynes—Cummings模型   总被引:6,自引:0,他引:6  
杨晓雪  吴颖 《光学学报》1998,18(8):050-1055
Cirac等人证明处于驻波光场波节处的单个囚禁两能级离子的动力学由Jaynes-Cum-mings(J-C)模型描述。本文旨在推广这一结论。通过引入穿衣态描述,证明处于驻波光场中任意位置时,单个囚禁的两能级离子的动力学仍由相同模型描述。  相似文献   

20.
郑著宏  范希武 《发光学报》1989,10(2):117-122
在77—300K温度范围内,用N2分子激光器的3371Å谱线激发未故意掺杂的p型ZnTe晶体,得到了与自由激子有关的发射。发现随着激发密度的增加,其发光光谱的峰值位置红移而谱带的半宽度展宽,这些结果可以用Ex—e和Ex—Ex的相互作用来解释。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号