电子束曝光剂量对NbN超导纳米线物性的影响

Influence of electron beam exposure dose on the properties of NbN superconducting nanowires

  • 摘要: 超导纳米线的可控制备是推动单光子探测器和量子相滑移器件等前沿应用的重要基础。作为实现纳米线图形化的核心技术,电子束光刻过程中电子束与超薄超导薄膜之间的相互作用可能对薄膜的本征物性产生不可忽略的影响。针对电子束曝光剂量对NbN超导纳米线超导性能及方块电阻的调控规律开展了系统研究。结果表明:随着曝光剂量的增加,NbN纳米线的正常态方块电阻显著增大(最大增幅达24%),伴随着相滑移激活能的降低;与此同时,尽管NbN纳米线的超导临界温度基本保持稳定,但其在极低温环境下对抗磁场的能力随曝光剂量的增加有所减弱。分析表明,高剂量曝光会在纳米线中引入缺陷,增强载流子散射,从而提高电阻。研究不仅为高性能超导纳米线器件的可控制备确定了最佳工艺窗口,也展示了电子束曝光作为一种潜在的局域化改性技术,可用于片上调控超导薄膜的无序度,为量子器件的设计与集成提供新的思路。

     

    Abstract: The controllable fabrication of superconducting nanowires is the key foundation for the high-performance applications such as single-photon detectors and quantum phase slip devices. Electron beam lithography, as a key technique for nanoscale patterning, may have a non-ignorable impact on the intrinsic physical properties of ultrathin superconducting films due to the interactions between the electron beam and the material. This study systematically examines how the electron beam exposure dose influences the superconducting properties and sheet resistance of NbN nanowires. The results show that, as the exposure dose increases, the normal-state sheet resistance of NbN nanowires significantly increases (with a maximum increase of 24%), acompanied by the reduce of activation energy of the phase slip. Meanwhile, although the superconducting critical temperature remains largely unchanged, the nanowires' ability to withstand magnetic fields at ultra-low temperatures diminishes with the increase of exposure dose. Analysis indicates that high-dose exposure introduces structural defects into the film, enhancing carrier scattering and thereby increasing electrical resistance. These findings not only define an optimal process window for fabricating high-performance superconducting nanowires but also highlight the potential of electron beam exposure as a localized method for tuning disorder in on-chip superconducting films, opening new possibilities for quantum device engineering.

     

/

返回文章
返回