Low threshold visible lasers are useful for a number of applications including full color mobile projectors, optical data storage, heads-up displays in automobiles, in medicine and plastic fiber communication. Lasers emitting in the blue and green are generally realized with GaN-based InGaN/GaN quantum wells (QWs) as the gain media. Self-organized quantum dots (QDs), which form by strain relaxation, offer distinct advantages over quantum wells and their emission can be extended to longer wavelengths (~ 630 nm). In this talk, we will describe the steady state and dynamic characteristics of green- and red-emitting InGaN/GaN quantum dot lasers. The determination of Auger recombination coefficients from large-signal modulation measurements made on the lasers will also be described. All quantum dot converter white LEDs will be described.
InGaN disks in GaN nanowires grown epitaxially on (001) silicon substrate have been exploited as the emission media in light emitting diodes. From structural and optical characterization we have confirmed that Volmer-Weber quantum dots are formed in the center of the InGaN disks. The emission wavelength of the dots can be varied from 530nm (green) to 1460nm (near-IR). We will describe the static and dynamic characteristics of edge-emitting electrically injected high performance visible and 1.3m dot-in-nanowire monolithic lasers grown directly on (001) silicon.BiographyPallab Bhattacharya is the Charles M. Vest Distinguished University Professor of Electrical Engineering and Computer Science and the James R. Mellor Professor of Engineering in the Department of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor. He received the M. Eng. and Ph.D. degrees from the University of Sheffield, UK. He has authored the textbook Semiconductor Optoelectronic Devices (Prentice Hall, 2nd edition). His teaching and research interests are in the areas of compound semiconductors, low-dimensional quantum confined systems, nanophotonics and optoelectronic integrated circuits. Professor Bhattacharya is a member of the US National Academy of Engineering. He has received numerous professional awards including the John Simon Guggenheim Fellowship, the Heinrich Welker Medal, the IEEE David Sarnoff Award, the Optical Society of America Nick Holonyak Award and the TMS John Bardeen Award. He is a Fellow of the IEEE, the American Physical Society, the Institute of Physics (UK), and the Optical Society of America.