Diamondoids and Diamond Color Centers
Diamondoids are cage-like hydrocarbon molecules with a C–C frame resembling the diamond lattice — they are essentially molecular-size diamonds. They have exhibited a variety of unique properties such as monochromatic photoemission [1-2] and ultra-strong van der Waals interaction that enables unique chemical bond formation . Monochromatic photoemission has been used to establish the highest resolution on X-PEEM by coating surface of magnetic domain sample with Self Assembly Monolayers of diamondoids .
We have the capability to separate, uniquely identify, and chemically functionalize a large group of this family of molecules. We have been interested in several perspectives regarding the physics, chemistry, and applications of this novel type of diamond materials, including:
- diamondoid-modulated self-assembly of low-dimensional nanostructures,
- diamondoid-seeded growth of high-purity diamond, and
- the development of diamondoid-enabled stable monochromatic photoemitter as a practical electron source for microscopy and lithographic applications.
Diamond Color Centers
The diamond color center is useful for future quantum and biological technologies. The nitrogen-vacancy center in diamond has been demonstrated to be a promising platform for quantum sensing and magnetometry, while negatively charged silicon-, germanium-, lead-, and tin-vacancies have favorable optical properties and robustness to electric field fluctuations. This is applicable in realizing future large-scale optical quantum information processing applications.
In the past decade, our group has developed a complete material synthesis pipeline to incorporate a variety of color centers in diamond nanoparticles and bulk diamond plates. Our 'vertical growth' method successfully embedded optically active nitrogen-vacancy centers in high-quality diamond nanoparticles as small as 75 nm . Recently, by combining the 'shallow ion implantation and growth' (SIIG) method with undercut fabrication technology, negatively charged tin-vacancies have been incorporated into a free-standing nano-beam device. This quantum device demonstrates superior optical properties and long spin coherence time at a temperature above 1 K [5-6].
 W. L. Yang et al. Monochromatic electron photoemission from diamondoid monolayers. Science 316, 1460 (2007)
 W. A. Clay et al. The origin of monochromatic photoemission peak in diamondod monolayer. Nano Lett. 9, 56 (2009)
 H. Ishiwata et al. Diamondoid coating enables disruptive approach for chemical and magnetic imaging with 10 nm spatial resolution. Appl. Phys. Lett. 101, 163101 (2012)
 Tzeng, Yan-Kai et al. Vertical-substrate MPCVD epitaxial nanodiamond growth. Nano letters 17(3), 1489 (2017)
 Rugar, Alison E. et al. Generation of Tin-Vacancy Centers in Diamond via Shallow Ion Implantation and Subsequent Diamond Overgrowth. Nano letters 20(3), 1614 (2020).
 Rugar, Alison E. et al. Narrow-linewidth tin-vacancy centers in a diamond waveguide. (Submitted)
 P. R. Schreiner et al. Overcoming lability of extremely long alkane carbon-carbon bonds through dispersion forces. Nature 477, 308 (2011)