X-Ray Spectroscopy of NiO and Nanodiamond at SSRL

The first aspect of this research project focuses on investigating the surface chemistry of high pressure high temperature (HPHT) nanodiamond by using X-ray spectroscopy techniques at the Stanford Synchrotron Radiation Lightsource (SSRL). HPHT nanodiamond is being examined as a biosensing tool for electric field detection based on the fluorescent nitrogen vacancy center hosted within diamond. With use of the transition edge spectrometer (TES), a state-of-the-art X-ray fluorescence detector, we are able to probe the surface and bulk properties of diamond. Preliminary work using density functional theory (DFT) has been done, offering insight into ground state energies and electronic structure. DFT will be used to perform future calculations. The second aspect of this research project investigates effects like saturation which distorts the true X-ray fluorescence-yield absorption spectrum, as well as various probing geometries with attention directed towards dilute samples of nickel oxide mixed with graphite. A typical method used to analyze the electronic structure of materials is electron yield detection. However, due to limitations in the escape depth of the electrons in such a method, the overall electron yield spectra is unrepresentative of bulk properties. Thus, we shift techniques to that of florescence yield detection. These two research endeavors serve to improve XAS techniques and advance nanodiamond for medical applications