100 MHz large bandwidth preamplifier and record-breaking 50 kHz scanning rate quantum point contact mode probe microscopy imaging with atomic resolution

Quan Feng Li; Yang Wang; Fang Wang; Yubin Hou; Qingyou Lu

doi:10.1063/5.0024802

100 MHz large bandwidth preamplifier and record-breaking 50 kHz scanning rate quantum point contact mode probe microscopy imaging with atomic resolution

Rev Sci Instrum. 2021 Jan 1;92(1):013701. doi: 10.1063/5.0024802.

Authors

Quan Feng Li¹, Yang Wang¹, Fang Wang², Yubin Hou³, Qingyou Lu³

Affiliations

¹ Henan Key Laboratory of Photovoltaic Materials, School of Physics, Henan Normal University, Xinxiang 453007, People's Republic of China.
² College of Electronic and Electrical Engineering, Henan Normal University, Xinxiang 453007, Henan, People's Republic of China.
³ Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China.

PMID: 33514189
DOI: 10.1063/5.0024802

Abstract

The high-bandwidth preamplifier is a vital component designed to increase the scanning speed of a high-speed scanning tunneling microscope (STM). However, the bandwidth is limited not only by the characteristic GΩ feedback resistor R_F but also by the characteristic unity-gain-stable operational amplifier (UGS-OPA) in the STM preamplifier. Here, we report that paralleling a resistor with the tunneling junction (PRTJ) can break both limitations. Then, the UGS-OPA can be replaced by a higher rate, higher antinoise ability, decompensated OPA. By doing so, a bandwidth of more than 100 MHz was achieved in the STM preamplifier with decompensated OPA657, and a higher bandwidth is possible. High-clarity atomic resolution STM images were obtained under about 10 MHz bandwidth and quantum point contact microscopy mode with a record-breaking line rate of 50 k lines/s and a record-breaking frame rate of 250 frames/s. Both the PRTJ method and the decompensated OPA will pave the way for higher scanning speeds and play a key role in the design of high-performance STMs.