Field emission from graphene produced with use of chemical vapor deposition method

The influence of graphene deposition on emission spectrum of Cu electrodes was investigated. In this order the two types of samples were prepared: one from a pure copper plate, and one from a copper plate covered with graphene. The graphene has been obtained using Chemical Vapor Deposition (CVD) method. The analysis of I=f(E) and Fowler-Nordheim (F-N) characteristics showed that a graphene layer uniformly deposited on a cathode, parallel to its surface creates a shielding for microprotrusions which causes a decrease of electric field and, consequently, the β coefficient. This occurs regardless whether the sample surface had been etched before graphene deposition or not. The F-N characteristics showed that the cathode emission mechanism is changing with the increase of field intensity. Initially, the emission current is blocked by a surface adsorption layer. With further increase of the field intensity, up the Eth value, a typical F- N mechanism occurs until microdischarges appear. As a result of microdischarges, under the influence of cathode potential, electrons are emitted, which bombard the anode. This current has a form of pulses repeated approximately every 4.5 ns until plasma is created on anode, what is in fact equivalent to a breakdown.