EAGER: Manufacturing of Diamond Nanocrystals for Quantum Applications

This EArly-concept Grants for Exploratory Research (EAGER) award aims at studying the fundamental science and engineering for nanomanufacturing of diamond crystal arrays for use in many novel applications, such as, quantum computing, magnetic field sensing, spintronics, encryption, and nanomedicine. Diamond nanocrystals containing nitrogen-vacancy (NV) defect centers display properties that can be controlled by microwave, optical signal, electric and magnetic fields thereby making them useful for a myriad of quantum applications.

To function as components of quantum devices, each nanometer or micrometer size diamond single crystal should preferably contain only one type of NV defect center and, when arranged into isolated diamond single crystal arrays, achieve the greatest sensitivity and individual addressability. This project develops approaches to manufacture diamond single crystal arrays containing NV defect centers that are preferentially oriented along a single crystallographic direction.

In addition, the project provides education and training to graduate and undergraduate students towards workforce development and careers in academia or industry. The research findings are disseminated to the scientific community and expected to have significant impacts on several national initiatives such as advanced manufacturing, nanotechnology, quantum information sciences, optoelectronics, medicine, and national security.

The state-of-the-art in quantum technology employs diamond thin films or bulk crystals containing NV defects that are unsuited for wide-spread use because the NV defects are randomly distributed and cannot be individually addressed for many of the novel quantum applications. The objective of the project is to demonstrate proof-of-concept for manufacturing of epitaxial diamond single crystal arrays with enhanced preferred orientation of the NV defect centers.

The scientific justifications for the overall program are based on three transformative hypotheses that include (1) bias-enhanced nucleation for creating an array of epitaxial diamond nuclei on patterned single crystal silicon substrates followed by the growth of the diamond crystals; (2) role of substrate orientations promoting preferential orientation of the NV defect centers along <111> crystallographic direction based on planar atom density; and (3) application of electric and/or magnetic fields during manufacturing by Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) for additional preferential alignment of the NV defect centers. The project advances the fundamental understanding of the roles of in situ doping by nitrogen, diamond nucleation and growth mechanisms, substrate orientation, and applied electric and/or magnetic fields on the NV defect centers.

The quality of the diamond nanocrystals is determined by quantitative characterization of spin state addressability based on changes in optical emission upon exposure of the nanocrystals to microwave and laser pumping using optically detected magnetic resonance.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.