InGaN/GaN nanorod and nanosheet arrays for InGaN-based LEDs

Abstract

GaN nanorods have drawn attention as possible crystalline structures on which to form InGaN active regions for LEDs, making use of the m-planes that form the sidewalls of the rods. In this paper, we describe such nanorods as well as nanosheets with increased m-plane surface area formed on c-plane sapphire. Non polar crystalline planes on nanorods and nanosheets are expected to lead to more efficient LEDs by enabling the formation of higher efficiency nonpolar active regions in three dimensional structures. The potential for increased efficiency derives from the reduction of quantum well band structure distortion that results from their formation on non-polar planes as well as the increase in the junction active area per chip by the inherent three dimensional nature of the nanostructures. Three dimensional active areas that are an order of magnitude greater than the chip area will reduce the current density at a given drive current and reduce the effects of efficiency “droop”. This increase is expected to add to efficiency improvements that derive from quantum wells on non-polar planes.