MIT and Columbia University Scientists Report Fabrication of High Purity Diamond Nanocrystals with Long-lived Spin State Suitable Quantum Computing

Problem: It is well-known that exposure to ionizing radiation can damage microelectronic devices. Less well known are the mechanisms causing the damage and reliable means to characterize radiation damage, especially for newer classes of materials being exploited for electronic applications such as graphene, complex metal oxides and diamond. DTRA has funded basic research to elucidate the mechanisms and characterization of radiation damage to emerging electronic materials. A by-product of the research is the production of diamond pillars with unprecedented electron spin durations.

Electron micrograph showing nanometer scale diamond pillars used in a prototype magnetic field sensor. (M. E. Trusheim, et. al., Nano Lett. 14(1), 32-36 (2014).)

Results: To conduct their mechanistic and characterization studies, Richard Osgood of Columbia University and Dirk Englund of MIT have developed materials preparation techniques when necessary. Englund's team has come up with a better means to produce high purity nanodiamond materials. The technique is now being commercialized by Diamond Nanotechnologies in Boston, Massachusetts, a company Englund founded with a former postdoctoral fellow from his laboratory. The technique works as follows. Gold palladium dots are deposited over pure diamond and then the diamond surfaces left exposed are etched away leaving a series of gold-topped diamond posts. The gold tops are easily removed to produce individual, nanometer-scale diamond pillars. When made in this way, the electrons trapped in the diamond defects hold their spin for 100 times longer than those in conventional nanodiamonds (Nano Lett., 2014, 14(1), pp 32–36). Diamond Nanotechnologies is using these pillars to build a prototype magnetic field sensor that is sensitive enough to detect the field from just a few electrons.

Potential: The nanodiamond materials produced in accordance with Englund’s method have the potential to be used in rad-hard quantum computing applications by capitalizing on the quantum entanglement of the trapped electrons in the array of diamond nano-pillars.

Transition/Impact: In addition to being transitioned into a commercial company for use as magnetic field sensors, the nanodiamond materials resulting from the DTRA-sponsored research have been featured in a Nature News Feature (Nature, 2014, 505, pp 472-474) discussing the promise of ultra-pure synthetic diamonds for applications ranging from quantum computing to cancer diagnostics.