Field emission mechanism of oxidized highly phosphorus-doped homoepitaxial diamond (111)

Spatially resolved electron field emission experiments on oxidized highly phosphorus-doped homoepitaxial diamond (111) were applied at room temperature. The diamond layer shows hopping conductivity. Field emission properties have three distinct regions. We attribute the variation in emission currents to: (a) Electron emission from conduction-band minimum (Region I), (b) Depletion of conduction-band electrons at the surface (Region II), and (c) emission from the phosphorus level (Region III). From these data, we calculate an effective positive electron affinity for the oxidized surface of 1 - 1.5 eV .