Nanodiamond photoemitters based on strong narrow-band luminescence from silicon-vacancy defects

Abstract

A study was conducted to examine the luminescence of silicon-vacancy (Si-V) defects and its stability in CVD diamond nanocrystals. Two CVD films samples including ultra-nanocrystalline diamond (UNCD) with grain size of 2-5 nm and microcrystalline diamond (MCD) with a grain size of 1μm were used for the study. The Raman spectrum for the UNCD films indicated three carbon phases including diamond, amorphous carbon, and polyacetylene. It was observed during the study that Si and Si-V type defects were unstable in bucky-diamond. Explicit computer simulations using the density-functional-based tight-binding method with self-consistent charges (SCC-DFTB) were carried out to compare the thermodynamic stability of the Si-related defects in diamond nanoparticles. It was found that Si-V defects can be formed and remained stable within the nanodiamond core.