LOW DIMENSION STRUCTURES AND DIVICES FOR NEW GENERATION PHOTONIC TECHNOLOGY

Abstract

Low dimensional structures and devices are the key technological building blocks for new generation of electronic and photonic technology. Such structures and devices show novel properties and can be integrated into systems for wide applications. In this talk, I will present the main results achieved in our competitive research program which aims to explore the application of the mesoscopic structures in light source, manipulation and imaging and integrate them into advanced systems. In light source, we have for the first time developed grapheme mode-locked lasers and black and white lasers. We also developed Si light emitting devices with external quantum efficiency of about 2.9×10^-3 % for visible emission at room temperature and the colour of emitted light can be tuned electrically from violet to white by varying the injected current.  In light manipulation, loss compensation of surface plasmon polaritons (SPPs) using quantum well (QW) gain media was studied theoretically and demonstrated experimentally. The SPP propagation length was, for the first time, effectively elongated several times through electrical pump. One and two microring resonators based on silicon on insulator and III-V semiconductors technologies have been successfully fabricated and they can be used as filter and switch in the photonic circuit. In imaging, both SPP and low dimension structures are investigated and resolution far beyond diffraction limit in visible range has been realized. Dilute nitride materials and their application for photodetection are explored.

ZHANG Dao Hua received M.S degree from Shandong University, China, and Ph.D degree from the University of New South Wales, Australia. He joined the School of Electrical and Electronic Engineering, Nanyang Technological University in 1991. He is currently the Director of Photonic Nano-structure and Applications program and the Lead PI of a $10 million Competitive Research Program. He is the Fellow of Institute of Physics and International evaluation panel member for fellowship.

His research interests include semiconductor materials and devices, nano-materials, nano-structures and applications. He has authored and co-authored over 300 international journal and conference papers, two books and two book chapters. He has served as Editor and guest editor for 6 international journals, including Thin Solid Films and Journal of Crystal Growth. He has been chair and co-chair of several international conferences. He received several best paper awards and is the nominee of the Singapore President’ Technology Award.