Laser-driven engineering of vacancy and color-center defects in diamond
Leyla Çolakerol Arslan
Department of Physiscs, Gebze Technical University
Nitrogen-vacancy (NV) and silicon-vacancy (SiV) diamond color centers offer a flexible foundation for quantum sensing, photonics, and developing quantum technologies. However, it is still difficult to regulate the development and spatial engineering of these defects, especially when targeted and scalable processing is required. Here, using complementary optical and positron annihilation lifetime spectroscopy (PALS) studies, we explore laser-driven defect engineering in diamond, showing both the modification of intrinsic vacancy-related defects and the laser-assisted incorporation of an external impurity to form SiV centers. By creating vacancies and encouraging their migration through transient heating processes, nanosecond-pulsed 1064 nm irradiation of type IIa CVD diamond allows for localized sub-bandgap adjustment through nonlinear and defect-assisted absorption.
Photoluminescence measurements show a decrease in NVH-related emission and an increase in NV0 and NV-emission, which is compatible with laser-induced redistribution of defect populations linked to hydrogen, nitrogen, and vacancies. PALS measurements also show that vacancy-type defects undergo regular changes as laser exposure increases. These changes include positron lifetime shifts, defect-related intensity variations, and the appearance of a long-lifetime component linked to greater open-volume regions. These data are consistent with vacancy migration, NVHx dissociation, and hydrogen release and offer direct proof of laser-induced reorganization and aggregation of vacancy-related defects. In a complementary approach, a silicon-coated diamond surface was exposed to targeted laser irradiation, which allowed for laser-assisted silicon integration into the diamond lattice and the creation of SiV centers, as seen by the distinctive SiV photoluminescence about 738 nm. Together, these results demonstrate that nanosecond laser irradiation can serve not only as a tool for modifying the intrinsic defect landscape of diamond but also as a localized route for introducing selected impurities and generating optically active color centers. Together, these findings show that nanosecond laser irradiation can be used as a localized method of introducing certain impurities and producing optically active color centers, in addition to being a tool for altering the inherent defect landscape of diamond.
Short Bio:
Prof. Leyla C. Arslan’s current research focuses on laser-driven defect engineering in diamond; voltage control of magnetism in multiferroic heterostructures; the growth and electrical, structural, and magnetic properties of Heusler compounds; and chemiresistive and mass-sensitive gas sensors based on metal oxides.
She received her Ph.D. from Boston University and subsequently spent several years conducting research at the National Synchrotron Light Source (Brookhaven National Laboratory) and the Advanced Light Source (Lawrence Berkeley National Laboratory), where she employed a range of synchrotron-based spectroscopy techniques to investigate structural and electronic phenomena in nitrides and functional metal oxides. Following her Ph.D., she carried out molecular beam epitaxy growth of nitride semiconductors and investigated their surface structures using real-time x-ray studies. After joining the Department of Physics at Gebze Technical University in 2010, she established the Nanomagnetism and Spintronics Research Laboratory, which is equipped with a molecular beam epitaxy system integrated with x-ray photoelectron spectroscopy, as well as a low-temperature physical property measurement system and electron spin resonance facilities.
