AC signal characterization for optimization of a CMOS single-electron pump

Roy Murray,M D Stewart,Justin K Perron,Neil M Zimmerman

doi:10.1088/1361-6528/aa9e56

Roy Murray, M D Stewart + Show 2 more

Open Access

https://doi.org/10.1088/1361-6528/aa9e56

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Abstract

Pumping single electrons at a set rate is being widely pursued as an electrical current standard. Semiconductor charge pumps have been pursued in a variety of modes, including single gate ratchet, a variety of 2-gate ratchet pumps, and 2-gate turnstiles. Whether pumping with one or two AC signals, lower error rates can result from better knowledge of the properties of the AC signal at the device. In this work, we operated a CMOS single-electron pump with a 2-gate ratchet style measurement and used the results to characterize and optimize our two AC signals. Fitting this data at various frequencies revealed both a difference in signal path length and attenuation between our two AC lines. Using this data, we corrected for the difference in signal path length and attenuation by applying an offset in both the phase and the amplitude at the signal generator. Operating the device as a turnstile while using the optimized parameters determined from the 2-gate ratchet measurement led to much flatter, more robust charge pumping plateaus. This method was useful in tuning our device up for optimal charge pumping, and may prove useful to the semiconductor quantum dot community to determine signal attenuation and path differences at the device.

Highlights

Pumping single electrons at a known frequency is being widely pursued for a quantum based current standard [1, 2]
Using a simple model comparing the width of the ellipse seen in figure 2(a) to the spacing of the coulomb blockade oscillations, we find the current as a function of the AC amplitude and φ: I ef AC‐Gen‐g
Using the values of α and Δφ(f) that we found by optimizing the 2-gate ratchet pumping, we significantly increased the plateau width at all frequencies (figure 5(b))

Summary

Introduction

Pumping single electrons at a known frequency is being widely pursued for a quantum based current standard [1, 2]. We operated a CMOS single-electron pump with a 2-gate ratchet style measurement and used the results to characterize and optimize our two AC signals. Operating the device as a turnstile while using the optimized parameters determined from the 2gate ratchet measurement led to much flatter, more robust charge pumping plateaus.

Results

Conclusion