Affiliations

• Materials Science and Engineering

Education Profile

• Ph.D., Semiconductor Spectroscopy, University of Strathclyde, 2008
• M.S., Photonics and Optoelectronics Devices, Heriot-Watt University and University of St Andrews, 2002
• B.S., Physics and Education, Umm Al-Qura University, 1999

Research Interests

Professor Roqan's research interests include optical, magnetic and structural properties of wide bandgap semiconductors (mainly ZnO and GaN related materials), with an aim to improve the quality of the grown films and their luminescence and ferromagnetic properties. She uses energy-dispersive and wavelength-dispersive x-ray spectroscopy, as well as atomic force microscopy to characterize the materials and their surface morphologies Roqan's group is semiconductor and material spectroscopy group. Optical spectroscopy could identify the carrier mechanism such as carrier confinement behavior, quantum stark effect, carrier density and carrier injection. Moreover, we could also identify the effect of the width of the quantum well/barrier, the effect of the nanorod structure, the bandgap structure, the polarization effect, the interaction of defect bands in the spectra and the identification of their source by time-resolved spectroscopy (TRS), photoluminescence (PL) and photoluminescence excitation (PLE). Second and third Harmonic Generator and OPO facilities add additional laser tunability and allow us to carry out PLE and selective TRS measurements simultaneously. They use XRD, SQUID and SEM to study the structural characterizations. They study the role of defects and material structure on the optical, magnetic and structural properties of the materials that lead to understanding the behavior of the materials and optimizing the material/device structures.

Selected Publications

• Ajia, I. A., Edwards, P. R., Liu, Z., Yan, J. C., Martin, R. W., & Roqan, I. S. (2014). Excitonic localization in AlN-rich AlxGa1− xN/AlyGa1− yN multi-quantum-well grain boundaries. Applied Physics Letters, 105(12), 122111.
• Zhang, Z., Schwingenschlögl, U., & Roqan, I. S. (2014). Vacancy complexes induce long-range ferromagnetism in GaN. Journal of Applied Physics, 116(18), 183905.
• Muhammed, M. M., Peres, M., Yamashita, Y., Morishima, Y., Sato, S., Franco, N., ... & Roqan, I. S. (2014). High optical and structural quality of GaN epilayers grown on (2¯ 01) β-Ga2O3. Applied Physics Letters, 105(4), 042112.
• Miranda, S. M. C., Edwards, P. R., O'Donnell, K. P., Boćkowski, M., Alves, E., Roqan, I. S., ... & Lorenz, K. (2014). Sequential multiple-step europium ion implantation and annealing of GaN. Phys. Status Solidi C, 11(2), 253-257.
• Lorenz, K., Miranda, S. M. C., Alves, E., Roqan, I. S., O'Donnell, K. P., & Boćkowski, M. (2012, February). High pressure annealing of Europium implanted GaN. In SPIE OPTO (pp. 82620C-82620C). International Society for Optics and Photonics
• Melnikov, V. A., & Roqan, I. S. (2012, November). Lineshape Engineering in an All-Pass Ring Resonator with Backreflection Coupled to a Symmetrical Fabry-Perot Resonator. In Latin America Optics and Photonics Conference (pp. LT4B-2). Optical Society of America.
• Roqan, I. S., O'Donnell, K. P., Martin, R. W., Edwards, P. R., Song, S. F., Vantomme, A., ... & Boćkowski, M. (2010). Identification of the prime optical center in GaN: Eu 3+. Physical Review B, 81(8), 085209.