Covalently-Bonded Diaphite Nanoplatelet with Engineered Electronic Properties of Diamond

Abstract

Diamond, as a highly promising “extreme” semiconductor material, necessitates electronic property engineering to unleash its full potential in electronic and photonic devices. In this work, the diaphite nanoplatelet, consisting of (111) planes of diamond nanoplatelet covalently bonded with graphite (0001) planes, is facilely synthesized using one-step microwave plasma enhanced chemical vapor deposition method. The high-energy plasma created by the pillar plays a crucial role in the formation. Importantly, altered electronic and optical properties are determined in the diaphite nanoplatelet through electron energy loss spectrum, density functional theory calculations, and cathodoluminescence spectroscopy. It is revealed that the strong sp3/sp2-hybridized interfacial covalent bonding in the diaphite nanoplatelet induces the electron transfer from diamond to graphite. This modulates the electronic structure of the near-interface layer of diamond and triggers a new local trapping band below the conduction band minimum within the bandgap. Consequently, the covalently-bonded diaphite exhibits a different optical emission characteristic ranging from 2.5 to 3.64 eV, featuring a significant peak blueshift of 430 meV compared to the H-terminated diamond. This work demonstrates a novel method to engineer the electronic properties of diamond, opening avenues for functional semiconductor device applications of diamond.