Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Fermi Level Dynamics01:12

Fermi Level Dynamics

The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Fermi Level01:18

Fermi Level

The Fermi-Dirac function is represented by an S-shaped curve indicating the probability of an energy state being occupied by an electron at a given temperature. The Fermi level is the energy level at which there is a fifty percent chance of finding an electron, and it is positioned between the lower-energy valence band and the higher-energy conduction band.
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
Semiconductors01:22

Semiconductors

There is variation in the electrical conductivity of materials - metals, semiconductors, and insulators that are showcased with the help of the energy band diagrams.
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
Metal-Semiconductor Junctions01:24

Metal-Semiconductor Junctions

The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
Energy Bands in Solids01:01

Energy Bands in Solids

Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
 Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...
Band Theory02:35

Band Theory

When two or more atoms come together to form a molecule, their atomic orbitals combine and molecular orbitals of distinct energies result. In a solid, there are a large number of atoms, and therefore a large number of atomic orbitals that may be combined into molecular orbitals. These groups of molecular orbitals are so closely placed together to form continuous regions of energies, known as the bands.
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

From the physics of secondary electron emission to image contrasts in scanning electron microscopy.

Journal of electron microscopy·2012
Same author

About the mechanisms of charging in EPMA, SEM, and ESEM with their time evolution.

Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada·2009
Same author

On some contrast reversals in SEM: application to metal/insulator systems.

Ultramicroscopy·2008
Same author

Charging in scanning electron microscopy "from inside and outside".

Scanning·2004

Related Experiment Video

Updated: Jun 17, 2026

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
08:53

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

Published on: October 9, 2012

Material contrast in SEM: Fermi energy and work function effects.

Jacques Cazaux1

  • 1Department of Physics, Faculty of Sciences, BP 1039, 51687 Reims Cedex 2, France. jacques.cazaux@univ-reims.fr

Ultramicroscopy
|January 12, 2010
PubMed
Summary

Scanning electron microscope (SEM) imaging relies on secondary electron emission (SEE) yields, angular distribution, and work function effects to differentiate sample components. Gold appears brighter than silicon, and doping influences contrast in SEM images.

More Related Videos

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope
11:14

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Published on: May 28, 2016

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures
08:12

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures

Published on: December 5, 2015

Related Experiment Videos

Last Updated: Jun 17, 2026

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
08:53

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

Published on: October 9, 2012

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope
11:14

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Published on: May 28, 2016

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures
08:12

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures

Published on: December 5, 2015

Area of Science:

  • Materials Science
  • Surface Science
  • Electron Microscopy

Background:

  • Assigning grey levels in Scanning Electron Microscope (SEM) images to specific sample components is complex.
  • Image contrast depends on secondary electron emission (SEE) yields, collection efficiency, and work function differences.

Purpose of the Study:

  • To investigate the factors determining grey levels in SEM images.
  • To evaluate the secondary electron (SE) spectral and angular distributions for gold (Au) and silicon (Si).
  • To quantify the influence of work function on contrast in SEM imaging.

Main Methods:

  • Utilized equations for spectral and angular distributions of emitted SEs.
  • Calculated the collected fraction of SEs (k(alpha)) and voltage contact effect (k(phi)) for Au and Si.
  • Analyzed material-dependent SE spectra and work function effects.

Main Results:

  • Collected SE spectra are distorted compared to emitted spectra, with k(alpha) being material-dependent.
  • Gold exhibits a slightly larger k(alpha) than silicon for coaxial detection.
  • Work function differences create a doping contrast (C) up to 15% in Si p/n junctions.

Conclusions:

  • SEM image contrast is influenced by SEE yield, detection geometry, and work function.
  • Gold and other metals are expected to appear brighter than silicon and germanium.
  • The analysis provides a strategy for investigating electronic devices with known components.