Publications de Abhishek Grewal

Scanning Tunneling Microscopy for Molecules: Effects of Electron Propagation into Vacuum

Using scanning tunneling microscopy (STM), we experimentally and theoretically investigate isolated platinum phthalocyanine (PtPc) molecules adsorbed on an atomically thin NaCl(100) film vapor deposited on Au(111). We obtain good agreement between theory a ...

Amer Chemical Soc2024

Character of Electronic States in the Transport Gap of Molecules on Surfaces

Klaus Kern, Abhishek Grewal

We report on scanningtunneling microscopy (STM) topographs ofindividual metal phthalocyanines (MPc) on a thin salt (NaCl) filmadsorbed on a gold substrate, at tunneling energies within the molecule'selectronic transport gap. Theoretical models of increasin ...

AMER CHEMICAL SOC2023

Anionic character of the conduction band of sodium chloride

Klaus Kern, Abhishek Grewal

The alkali halides are ionic compounds. Each alkali atom donates an electron to a halogen atom, leading to ions with full shells. The valence band is mainly located on halogen atoms, while, in a traditional picture, the conduction band is mainly located on ...

Nature Portfolio2022

Single molecule fluorescence and phosphorescence studies using a scanning tunneling microscope

Abhishek Grewal

This thesis investigates novel single-molecule luminescence phenomena at their inherent, sub-molecular length scale. The microscopic understanding of luminescence processes will be crucial for the continued improvement of organic optoelectronic and semicon ...

EPFL2022

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

Klaus Kern, Markus Ternes, Abhishek Grewal

Combined scanning tunnelling and atomic force microscopy using a qPlus sensor enables the measurement of electronic and mechanic properties of two-dimensional materials at the nanoscale. In this work, we study hexagonal boron nitride (h-BN), an atomically ...

BEILSTEIN-INSTITUT2021

Gigahertz Frame Rate Imaging of Charge-Injection Dynamics in a Molecular Light Source

Klaus Kern, Markus Etzkorn, Anna Maria Roslawska, Abhishek Grewal

Light sources on the scale of single molecules can be addressed and characterized at their proper sub-nanometer scale by scanning tunneling microscopy-induced luminescence (STML). Such a source can be driven by defined short charge pulses while the lumines ...

AMER CHEMICAL SOC2021

Atomic-Scale Structural Fluctuations of a Plasmonic Cavity

Klaus Kern, Anna Maria Roslawska, Abhishek Grewal

Optical spectromicroscopies, which can reach atomic resolution due to plasmonic enhancement, are perturbed by spontaneous intensity modifications. Here, we study such fluctuations in plasmonic electroluminescence at the single-atom limit profiting from the ...

AMER CHEMICAL SOC2021

Gold Chain Formation via Local Lifting of Surface Reconstruction by Hot Electron Injection on H-2(D-2)/Au(111)

Klaus Kern, Anna Maria Roslawska, Abhishek Grewal

The hexagonal close packed surface of gold shows a 22 x root 3 "herringbone" surface reconstruction which makes it unique among the (111) surfaces of all metals. This long-range energetically favored dislocation pattern appears in response to the strong te ...

AMER CHEMICAL SOC2020

A Single Hydrogen Molecule as an Intensity Chopper in an Electrically Driven Plasmonic Nanocavity

Klaus Kern, Anna Maria Roslawska, Abhishek Grewal, Christoph Grosse

Photon statistics is a powerful tool for characterizing the emission dynamics of nanoscopic systems and their photophysics. Recent advances that combine correlation spectroscopy with scanning tunneling microscopy induced luminescence (STML) have allowed th ...

AMER CHEMICAL SOC2019