Transfer doping of diamond: The use of C60C60 and C60F36C60F36 to effect p-type surface conductivity

Ab initio density-functional theory is used to determine the suitability for transfer doping of diamond surfaces with various hydrogen and oxygen terminations. Transfer doping of the hydrogenated (0 0 1) diamond surface with C60C60 is investigated, and electron transfer from diamond to C60C60 (leaving a hole layer near the diamond surface) is predicted for a C60C60 coverage of about one monolayer. The efficiency of electron transfer is expected to increase for higher coverages. It is also shown that the greater electron affinity of fluorinated  C60C60 is likely to enhance the effect, in that C60F36C60F36 can extract electrons from hydrogenated diamond at much lower coverages. The consequences of oxygenation of the diamond surface on the transfer-doping properties of C60C60 are also investigated.