Ballistic electron emission microscopy
Encyclopedia
Ballistic electron emission microscopy or BEEM is a technique for studying ballistic electron transport through a variety of materials and material interfaces. BEEM is a three terminal scanning tunneling microscopy
(STM) technique that was invented in 1988 at the Jet Propulsion Laboratory
in Pasadena
California
by L. Douglas Bell and William Kaiser. The most popular interfaces to study are metal-semiconductor Schottky diode
s, but metal-insulator-semiconductor systems can be studied as well.
When performing BEEM, electrons are injected from a STM tip into a grounded metal base of a Schottky diode. A small fraction of these electrons will travel ballistically through the metal to the metal-semiconductor interface where they will encounter a Schottky barrier
. Those electrons with sufficient energy to surmount the Schottky barrier will be detected as the BEEM current. The atomic
scale positioning capability of the STM tip gives BEEM nanometer spatial resolution. In addition, the narrow energy distribution of electron
s tunneling from the STM tip gives BEEM a high energetic resolution (about 0.02 eV).
Microscopy
Microscopy is the technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye...
(STM) technique that was invented in 1988 at the Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...
in Pasadena
Pasadena
-Places:Places in Australia:*Pasadena, South Australia, a suburb of AdelaidePlaces in Canada:*Pasadena, NewfoundlandPlaces in the United States:*Pasadena, California*South Pasadena, California*South Pasadena, Florida*Pasadena, Maryland...
California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
by L. Douglas Bell and William Kaiser. The most popular interfaces to study are metal-semiconductor Schottky diode
Schottky diode
The Schottky diode is a semiconductor diode with a low forward voltage drop and a very fast switching action...
s, but metal-insulator-semiconductor systems can be studied as well.
When performing BEEM, electrons are injected from a STM tip into a grounded metal base of a Schottky diode. A small fraction of these electrons will travel ballistically through the metal to the metal-semiconductor interface where they will encounter a Schottky barrier
Schottky barrier
A Schottky barrier, named after Walter H. Schottky, is a potential barrier formed at a metal–semiconductor junction which has rectifying characteristics, suitable for use as a diode...
. Those electrons with sufficient energy to surmount the Schottky barrier will be detected as the BEEM current. The atomic
Atomic
Atomic may refer to:* Of or relating to the Atom, the smallest particle of a chemical element that retains its chemical properties* Atomic Age, also known as the "Atomic Era"* Atomic , an Australian computing and technology magazine...
scale positioning capability of the STM tip gives BEEM nanometer spatial resolution. In addition, the narrow energy distribution of electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s tunneling from the STM tip gives BEEM a high energetic resolution (about 0.02 eV).