Transfer doping of diamond via 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)

Hydrogen terminated diamonds exposed to atmosphere typically exhibit surface p-type conduction, thought to be due to transfer doping with holes in the surface valence band and negatively charged counter-ions in an adsorbed layer. The effect has been demonstrated with atmospheric contamination forming an aqueous layer, and by C-60 molecules. In this paper we show using first-principles computational methods that organic layers made up from DDQ molecules may also be a candidate for inducing holes in the diamond surface. The effect appears independent of surface orientation and surface coverage. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.