用于超导单光子探测器的氮化铌与铌硅薄膜制备研究

发布时间：2018-04-01 12:03

  本文选题：超导单光子探测器　切入点：NbN薄膜　出处：《南京大学》2015年硕士论文

【摘要】：单光子探测技术既具有重要的科学意义也有广泛的应用领域,在量子秘钥分发、量子计算、荧光探测、微弱光成像等方面均有重要作用。超导纳米线单光子探测器基于超导纳米线条中非平衡态的热电子效应,具有速度快、探测范围宽和暗记数低的优点,通过光学谐振腔或光学波导结构,系统探测效率也可达到80%以上,是目前综合性能最佳的单光子探测器,因此受到了学界关注。高质量的超导薄膜是制备超导单光子探测器的基础和关键。本文主要研究超薄的NbN薄膜和低能隙的NbSi薄膜的制备与表征,通过优化工艺条件,在多种衬底上制备出高质量的超薄NbN和NbSi薄膜。文中对两套制备系统的结构和操作方法都进行了详细介绍,并给出了两种薄膜的详细制备流程。我们使用台阶仪、能量色散X射线光谱仪(EDX)、X射线衍射仪(XRD)、原子力显微镜(AFM)和扫描电子显微镜(SEM)等手段系统表征了NbN和NbSi两种薄膜的厚度、结构、成分、表面形貌等性能；利用液氦杜瓦测量系统和综合物性测量系统(PPMS)表征了NbN和NbSi薄膜的超导转变温度。样品的实验测量表明,制备在MgO衬底上4nmNbN薄膜的超导转变温度超过12.5K,在Si衬底上6nmNbN薄膜的超导转变温度超过7.4K,在Si-SiOx衬底上6nmNbN薄膜的超导转变温度超过7.38K。利用共溅射工艺技术,通过调节溅射电压、溅射气压、靶材与衬底的距离等实验参数制备出NbSi薄膜,成分分析表明,薄膜成分含量为Nb占65%,Si占30%,超导转变温度也达到了3K,这些工作为开发红外及远红外波段的超导单光子探测器打下了良好基础。利用测量方阻法估算薄膜厚度,为超薄薄膜厚度的工艺检测提供了一个快捷方便的手段,并已应用于超导纳米线单光子探测器的制备中,获得很好效果。
[Abstract]:Single photon detection technology has important scientific significance as well as a wide range of applications in quantum secret key distribution, quantum computing, fluorescence detection, The single photon detector of superconducting nanowires is based on the thermionic effect of the nonequilibrium state of superconducting nanowires, which has the advantages of high speed, wide detection range and low number of dark memories. Through the optical resonator or optical waveguide structure, the detection efficiency of the system can also reach more than 80%, so it is the best single photon detector with the best comprehensive performance at present. Therefore, high quality superconducting thin films are the basis and key of preparing superconducting single photon detectors. In this paper, the preparation and characterization of ultra-thin NbN thin films and low energy gap NbSi thin films are studied. Ultrathin NbN and NbSi thin films with high quality have been prepared on various substrates. The structure and operation methods of the two preparation systems are introduced in detail, and the detailed preparation processes of the two kinds of thin films are given. The thickness, structure, composition and surface morphology of NbN and NbSi thin films were characterized by energy dispersive X-ray spectrometer (EDX), atomic force microscope (AFM) and scanning electron microscopy (SEM). The superconducting transition temperatures of NbN and NbSi thin films were characterized by liquid helium Dewar measurement system and comprehensive physical property measurement system. The superconducting transition temperature of 4nmNbN films on MgO substrates, 6nmNbN films on Si substrates and 6nmNbN films on Si-SiOx substrates is more than 12.5 K, 7.4 K and 7.38 K, respectively. NbSi thin films were prepared by sputtering pressure and the distance between target and substrate. The composition of the thin film is NB / 65 / Si / 30, and the superconducting transition temperature is 3K, which lays a good foundation for the development of infrared and far-infrared single-photon superconducting detectors. The thickness of the thin films is estimated by measuring the square resistance method. It provides a quick and convenient method for measuring the thickness of ultrathin film, and has been applied to the preparation of single photon detector of superconducting nanowires, and good results have been obtained.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM26;TB383.2

【参考文献】

相关硕士学位论文 前1条

1 马治军;NbN薄膜和NbN/SiN_x纳米多层膜的制备及性能研究[D];吉林大学;2008年

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