摘 要：研究表面声波单电子输运（SAW/SET）器件中的量子化声电电流对于揭示表面声波驱动的单电子输运特性有重要意义，并且有可能应用于量子电流基准，从而把安培与基本电荷和频率联系起来。为此设计了一种高精度高智能测量系统用于测量表面声波单电子输运器件中的声电电流。通过采用高性能I-V转换器和小波去噪等措施，使系统的噪声峰峰值小于30 fA；采用LabVIEW编写的测量程序和合适的硬件实现了智能化的自动测量。该系统已成功地应用到SAW/SET器件中弱电流的测量，为将来揭示表面声波驱动的单电子输运特性和量子电流基准的可能实现做了有益的探索。
Measurements of weak current based on single-electron transport driven by the surface-acoustic-wave
ZHAO Jian-jun1, ZHANG Lin1, YUAN Hui2, LI Ling3, GAO Jie1，2
（1.College of Physical Science and Technology，Sichuan University，Chengdu 610064，China;
2.National Institute of Measurement and Testing Technology，Chengdu 610021，China;
3.College of Physics and Lab. for Low-dimensional Structure Physics，Sichuan Normal University，Chengdu 610066，China)
Abstract： It is significant to study experimentally the quantized acoustoelectric current for the transport of single electron driven by the surface acoustic wave （SAW）. One of its possible applications is the development of a fundamental standard of electrical current linking the ampere to the elementary charge and frequency. We designed a precise, intelligent automatic system to measure the acoustoelectric current for SAW-driven single electron transport devices. The peak-to-peak value of the noise is less than 30 fA by using high-performance I-V conversion devices and the denoising methods of wavelet transform. The intelligent automatic measurements are realized by the programs of LabVIEW and appropriate hardwares. This measurement system has been successfully applied to measure the weak current in SAW/SET devices. The present work also has an impact on the future study on SAW-driven single electron transport and the possible realization of quantized current standard.
Key words: Surface acoustic wave； Single electron transport; Acoustoelectric current; Denoising methods of wavelet transform; Weak current measurement