Mechanism Of Highly Efficient Electron Emission From A Graphene/Oxide/Semiconductor Structure

Highly efficient electron emission of 48.5% was demonstrated by a graphene/oxide/semiconductor (GOS) structure. The main factors contributing to this performance were investigated by analyzing the energy distributions of the emitted electrons and the current conduction mechanism through the oxide layer. The energy level of the lower tail of the electron energy distribution was 2.4-2.6 eV above the work function of the graphene electrode, indicating that the work function of the gate electrode does not affect the electron emission efficiency. In addition, Fowler-Nordheim (FN) tunneling was the dominant current conduction mechanism in the oxide layer when the GOS structure exhibited highly efficient electron emission. These findings indicate that the high electron transmittance of the graphene electrode and the pure FN tunneling current through the oxide layer were responsible for the highly efficient electron emission from the GOS structure. These results further indicate the possibility of experimentally evaluating the low-energy electron transmittance of graphene with various layer numbers by analyzing the electron emission efficiency of the GOS structure. The maximum electron emission efficiency of the GOS structure was predicted to be approximately 70.3% using the high electron transmittance of single-layer graphene determined in this study.