Monolithic polychromatic light-emitting diodes based on InGaN microfacet quantum wells toward tailor-made solid-state lighting

Monolithic polychromatic light-emitting diodes (LEDs) based on micro-structured InGaN/GaN quantum wells are demonstrated. The microstructure is created through regrowth on SiO(2) mask stripes along the [1 (1) over bar 00] direction and consists of (0001) and {11 (2) over bar2} facets. The LEDs exhibit polychromatic emission, including white, due to the additive color mixture of facet-dependent emission colors. Altering the growth conditions and mask geometry easily controls the apparent emission color. Furthermore, simulations predict high light extraction efficiencies due to their three-dimensional structures. Those observations suggest that the proposed phosphor-free LEDs may lead to highly efficient solid-state lighting in which the color spectra of light sources are synthesized to satisfy specific requirements for illuminations. (c) 2008 The Japan Society of Applied Physics.