posted on 2021-06-24, 20:09authored byAnand B. Puthirath, Eliezer F. Oliveira, Guanhui Gao, Nithya Chakingal, Harikishan Kannan, Chenxi Li, Xiang Zhang, Abhijit Biswas, Mahesh R. Neupane, Bradford B. Pate, Dmitry A. Ruzmetov, A. Glen Birdwell, Tony G. Ivanov, Douglas S. Galvao, Robert Vajtai, Pulickel M. Ajayan
Oxygen
bonded with diamond surfaces impacts important properties
such as electrical conductivity, Schottky barrier height, field emission,
and chemical reactivity. Though processes such as thermal, hydrogen
plasma, etc., are efficient in oxidizing the hydrogen-terminated diamond
surfaces, the oxidation of pristine diamond surfaces through wet chemical
treatments is still in its infancy. Herein, we investigated the efficacy
of Hummer’s method, one of the most celebrated chemical oxidation
procedures to convert graphite to graphene oxide, to oxidize the pristine
diamond surfaces. We attempted to oxidize both microcrystalline diamond
powders and polycrystalline diamond wafers. Due to the presence of
an acidic oxidative environment and the formation of strong oxidizing
agents such as Mn2O7 and MnO3+ during the course of the reaction, Hummer’s method
is found to be very effective in oxidizing the pristine diamond surfaces.
The degree of oxygen termination is validated through various spectroscopic
and surface probe measurements. Microcrystalline diamond powder is
more prone to oxidation to polycrystalline diamond wafers due to excess
surface area, and many facets with different dangling bond densities
are exposed to the oxidizing medium. The experimental observations
are endorsed through molecular dynamics simulations.