Light Emitting Diode Growth on Curved Gallium Nitride Surfaces

Abstract

ABSTRACTIII-Nitride based Light Emitting Diodes (LEDs) are heavily pursued for various lighting applications due to the ability to engineer the emission through the visible wavelengths by controlling the alloy composition in the multi quantum well. Planar structures are characterized by a Lambertian emission pattern, however, depending on the applications in which the LED is employed, including but not limited to, general lighting, displays, and sensors, the emission profile may need to be more or less directional. As a result, there is significant interest in both improving the efficiency and controlling the emission profile of nitride based devices. Various components such as lenses and photonic crystals are used to improve light extraction and alter the emission profile while growth on semi-polar substrates is being pursued to minimize inherent polarization effects. In this work, curved Gallium Nitride (GaN) structures have been grown utilizing growth kinetics. These as-grown features do not require the extensive additional fabrication and allow for three-dimensional substrates to be employed for LED fabrication. The details of the fabrication and the optical and electrical characterization of Indium Gallium Nitride based LEDs grown on these structures is discussed.