Molecular Electronics

Research Interests

The aim of molecular electronics is to use individual molecules as building blocks for nanometer-scale electrical circuits. Recent studies have demonstrated that the atomic structure of the electrodes contacting the molecule and the nature of the molecule-electrode bond can have a dominant effect on the electrical properties of such a system. In order to better understand the relationship between structure and function in molecular devices, we aim to develop a three terminal device, whose structure will be characterized with atomic resolution. This device is to be comprised of a molecule attached to two vacuum deposited nanowires, which will serve as the source and the drain; an SPM (scanning probe microscope) tip will act as a gate. The detailed atomic structure of the device will be taken into consideration in our models, performed in collaboration with Hong Guo at McGill University. The hope is to help bridge the gap between theory and experiment which still exists in this field.

The Atomic Manipulation Facility

The centerpiece of the atomic manipulation facility is a custom built JEOL JSPM-4500A ultrahigh vacuum, low temperature, surface science system. This instrument consists of several standard surface science tools, along with an AFM (atomic force microscope), an STM (scanning tunneling micrscope) and an FE-SEM (field emission-secondary electron microscope) which allows the AFM or STM tip to be accurately positioned over regions of interest on a sample.


General

  • Three chamber ultrahigh vacuum system: quick load lock chamber, specimen treatment chamber, analysis chamber
  • Base pressure in treatment and analysis chambers less than 10e-8 Pa

Specimen Treatment Chamber

  • LEED/Auger spectrometer
  • Four-source e-beam evaporator for the deposition of metals
  • Three source evaporator for the deposition of organic molecules
  • Quartz crystal deposition monitor for determining thickness of evaporated films
  • Ion gun
  • Specimen cleaving device
  • In situ mask system for depositing macroscopic electrode patterns (designed in-house)

Analysis Chamber

  • AFM: frequency modulated atomic force microscopy (NC-AFM), contact mode, tapping mode, magnetic force microscopy, electric force microscopy, Kelvin force microscopy, friction force microscopy, phase detection, current image
  • STM: I-V, S-V, I-S, CITS
  • Field emission SEM, designed for observing tip and/or sample on SPM stage.
  • Imaging can be performed at temperatures ranging from 30 K to 800 K
  • Nanonis SPM Control System with dual PLL

People

Group Members

  • Zeno Schumacher (PhD student)
  • Andreas Spielhofer (PhD student)
  • Rasa Rejali (Master student)

Former Group Members

Collaborators

Recent publications