• 文献标题:   Measuring and Tuning the Potential Landscape of Electrostatically Defined Quantum Dots in Graphene
  • 文献类型:   Article
  • 作  者:   BEHN WA, KREBS ZJ, SMITH KJ, WATANABE K, TANIGUCHI T, BRAR VW
  • 作者关键词:   2d material, quantum dot, surface potential, kelvin probe force microscopy, scanning tunneling spectroscopy, graphene
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:  
  • 被引频次:   2
  • DOI:   10.1021/acs.nanolett.1c00791 EA JUN 2021
  • 出版年:   2021

▎ 摘  要

We use Kelvin probe force microscopy (KPFM) to probe the carrier-dependent potential of an electrostatically defined quantum dot (QD) in a graphene/hexagonal boron nitride (hBN) heterostructure. We show that gate-dependent measurements enable a calibration scheme that corrects for uncertainty inherent in typical KPFM measurements and accurately reconstructs the potential well profile. Our measurements reveal how the well changes with carrier concentration, which we associate with the nonlinear dependence of graphene's work function on carrier density. These changes shift the energy levels of quasi-bound states in the QD which we can measure via scanning tunneling spectroscopy (STS). We show that the experimentally extracted energy levels closely compare with wave functions calculated from the reconstructed KPFM data. This methodology, where KPFM and STS data are simultaneously acquired from 2D materials, allows the quasiparticle response to an electrostatic potential to be determined in a self-consistent way.