On the metastability of the surface conductivity in hydrogen-terminated polycrystalline CVD diamond

Hydrogen-termination of diamond is known to lead to high room-temperature surface conduction. However, this is metastable against pressure and temperature, and the origin and the related mechanisms are still a matter of debate. We here examine how the surface conduction recovers after heating under vacuum by the exposure to air, ozone, and UV illumination and we also present the results of conductance measurements performed during a subsequent heating and cooling cycle. Both exposures to ozone and UV light are found to accelerate the process of surface conduction recovery, suggesting that oxygen-related adsorbed species together with a charge transfer process are responsible for the formation of the surface hole accumulation layer. (C) 2004 Elsevier B.V. All rights reserved.