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  • Tuesday, October 9, 2018
  • 3:45 PM–4:45 PM
  • SB110

Join us on Tuesday, October 9 at 3:45 in SB 110 to hear a seminar given by three students and two professors from Calvin College and Hope College.  Brian Seper, Ivan Lainez Aleman & Dr. Ryan Balili,  of Calvin College and Forest Rulison & Dr. Paul DeYoung, of Hope College will speak about their project, “Identification of Photo-Initializable Point Defects in Carbon Related  Materials by Optically-Detected Magnetic Resonance." Refreshments will be available in SB 157 at 3:30 p.m.


This is Professor Balilii’s abstract:

 Point defects in carbon related materials, such as diamond and SiC, have recently caught the interest of a rapidly growing field of carbon-based technology and nanoscale biological sensing applications because of the defect center’s unique combination of properties which includes high temperature operation, stability and high sensitivity to magnetic or electric fields. To probe defect centers of various materials, we built an Optically Detected Magnetic Resonance (ODMR) setup to initialize, manipulate and investigate the photo-spin characteristics of various defect centers. Magnetic fields were used to shift the energy levels of the spin states and microwaves were applied to flip the electron populations between the states. We present important physical phenomena that occur in nitrogen-vacancy point defects (NV centers) in nanodiamond, such as the Zeeman effect, photo-initialization of spin states, optically detected electron spin resonance, and Rabi oscillations to illustrate the NMR-like capabilities of point defects. The data on our nanodiamond NV centers show electron spin resonance at 2.875 GHz at a zero magnetic field environment, corroborating published results. Well-known results of diamond NV centers, such as its spin resonance, were used to optimize our ODMR setup and to calibrate our measurements on other defects we have created materials such as silicon carbide. Preliminary data on silicon-vacancy-type defects on silicon carbide (6H-SiC) samples, irradiated with ionized hydrogen and helium (H+, Alpha 1+) through our Calvin-Hope College collaboration, will be presented. The irradiation energy, fluence, and irradiation particles (H+, Alpha 1+) were systematically varied to arrive at an optimum setting for creating single defects, di-vacancies, or defect clusters on various silicon carbide polytypes (6H, 4H, 3C).  Here we present all the preliminary results of our effort to identify and characterize SiC point defects using our ODMR setup in search for NMR-like features that are on par or better than NV center point defects.


Location details

Science Building Room 110

October 2018
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