Control of Scanning Quantum Dot Microscopy

TL;DR

This paper introduces a novel control framework for scanning quantum dot microscopy, significantly improving scan speed and area coverage by integrating feedforward and feedback control strategies.

Contribution

It develops a two-degree-of-freedom control approach with tailored controllers, enhancing the precision and efficiency of quantum dot microscopy.

Findings

Control framework speeds up scanning by over ten times

Enables large-area high-resolution imaging

Improves quantitative accuracy of electrostatic potential measurements

Abstract

Scanning quantum dot microscopy is a recently developed high-resolution microscopy technique that is based on atomic force microscopy and is capable of imaging the electrostatic potential of nanostructures like molecules or single atoms. Recently, it could be shown that it not only yields qualitatively but also quantitatively cutting edge images even on an atomic level. In this paper we present how control is a key enabling element to this. The developed control approach consists of a two-degree-of-freedom control framework that comprises a feedforward and a feedback part. For the latter we design two tailored feedback controllers. The feedforward part generates a reference for the current scanned line based on the previously scanned one. We discuss in detail various aspects of the presented control approach and its implications for scanning quantum dot microscopy. We evaluate the influence of the feedforward part and compare the two proposed feedback controllers. The proposed control algorithms speed up scanning quantum dot microscopy by more than a magnitude and enable to scan large sample areas.