In this case, I am concerned with the field emission from graphene.

Dear Sanjay

The note of ALAM is okay.

In order for a metal to emit electrons one has to supply the electrons inside the metal by an amount of energy called the work function of the metal as these electrons are bound to the host atoms. This energy can be supplied to the metal in form of heating. Electron emission because of heating is called thermionic emission. It is used in electronic vacuum tubes and displays. The electrons can also be emitted when the material is exposed to light with photon energy greater than the work function. This type of emission is called photo emission. It is widely used in photo detectors. The third and last type of electron emission is field emission where it is observed that by increasing the electric field normal to the metal surface to certain critical electric field electrons can be released from the interior of the metal. Increasing the electric field decreases the width of the potential barrier at the surface of the metal to the limit such that electrons can tunnel such barrier and freed from the metal .Field emission is an electronic phenomenon which is used to make useful electronic devices. Examples are the tunnel diode, the Zener breakdown diode, the backward diode, the field emission microscope and the cold cathode micrometer tubes,...etc. As an electronic phenomenon, It belongs to solid state electronics

Thank you