Department of Physics, Interdepartmental Centre NIS, University of Torino , via Giuria 1, I-10125 Torino, Italy.
Nano Lett. 2014 Mar 12;14(3):1583-9. doi: 10.1021/nl404834u. Epub 2014 Mar 3.
We describe the controlled use of a 17 keV X-ray synchrotron nanobeam to progressively change the oxygen doping level in Bi-2212 superconducting whisker-like single crystals. Our data combine structural and electrical information collected on the same crystals, showing a maximum change in the critical temperature Tc of 1.3 K and a maximum elongation of ∼1 Å in the c-axis length, compared to the as-grown conditions. Simulations of our experimental conditions by means of a finite element model exclude local heating induced by the X-ray nanobeam as a possible cause for the change in the doping level and suggest an important role of secondary electrons. These findings support the possible use of hard X-rays as a novel direct-writing, photoresist-free lithographic process for the fabrication of superconducting devices, with potential nanometric resolution and 3D capability.
我们描述了对 17keV X 射线同步加速器纳米束的控制使用，以逐步改变 Bi-2212 超导晶须状单晶中的氧掺杂水平。我们的数据结合了在同一晶体上收集的结构和电学信息，与原始生长条件相比，Tc 的临界温度最大变化为 1.3K，c 轴长度的最大伸长约为 1Å。通过有限元模型对我们的实验条件进行的模拟排除了 X 射线纳米束引起的局部加热作为掺杂水平变化的可能原因，并表明二次电子的重要作用。这些发现支持将硬 X 射线用作制造超导器件的新型无光刻胶直接写入光刻工艺，具有潜在的纳米级分辨率和 3D 能力。
