Electroless oxidation of boron-doped diamond surfaces: comparison between four oxidizing agents; Ce4+, MnO4−, H2O2 and S2O82−

The electrochemical properties of diamond are very sensitive to the surface terminations. It is still a challenge to successfully produce well-defined “C–O” functions. In this paper, we describe and compare the oxidation of as-grown polycrystalline boron-doped diamond (BDD) films using four different oxidizing agents in aqueous media: Ce4+, MnO4−, H2O2 and S2O82−. The different treatments lead to the formation of oxygenated functions at the diamond surface, mainly singly oxidized “C–O” groups such as “C–OH” or “C–O–C”. Processes with Ce4+ and MnO4− seem to be particularly interesting as they both lead to the creation of a high amount of oxygenated functions and an improvement of the charge transfer at BDD surfaces.

Research highlights
► C–O functions can be produced on BDD films by simple dipping in a aqueous solution containing a chosen oxidizing specie.
► Mainly singly oxidized groups “C–O” are formed during the oxidation process.
► The oxidation mechanism is not always the same with all the oxidizing agents.
► This method can be used on either conductive or not diamond films.