Pallab Bhattacharya 2015-2016 Seminar Series
February 18, 2016
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.