Stabilizing diamond surface conductivity by phenol-formaldehyde and acrylate resins

H-terminated undoped nano-crystalline diamond films of 200 nm thickness are deposited by microwave plasma chemical vapor deposition on fused silica substrates seeded by a diamond powder. The films exhibit surface conductivity 10− 7 (Ω/□)− 1. Phenol-formaldehyde and acrylate resins are spin-coated on the diamond films in the thickness of 0.2–1.7 μm. After the coating, the surface conductivity changes by − 12% to + 52% compared to a bare diamond surface. It also exhibits significantly higher temporal stability. These effects are attributed to an encapsulation of the surface conductive channel from the ambient and to an electrostatic field of molecular dipoles in the resins.