摘 要：研究表面聲波單電子輸運(yùn)（SAW/SET）器件中的量子化聲電電流對于揭示表面聲波驅(qū)動的單電子輸運(yùn)特性有重要意義，并且有可能應(yīng)用于量子電流基準(zhǔn)，從而把安培與基本電荷和頻率聯(lián)系起來。為此設(shè)計(jì)了一種高精度高智能測量系統(tǒng)用于測量表面聲波單電子輸運(yùn)器件中的聲電電流。通過采用高性能I-V轉(zhuǎn)換器和小波去噪等措施，使系統(tǒng)的噪聲峰峰值小于30 fA；采用LabVIEW編寫的測量程序和合適的硬件實(shí)現(xiàn)了智能化的自動測量。該系統(tǒng)已成功地應(yīng)用到SAW/SET器件中弱電流的測量，為將來揭示表面聲波驅(qū)動的單電子輸運(yùn)特性和量子電流基準(zhǔn)的可能實(shí)現(xiàn)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
