GaN monolithic integration for lighting and display

Abstract

Light-emitting diodes based on InGaN/GaN quantum wells are widely used for lighting and display applications. However, such LEDs are monochromatic with relatively narrow spectral line-widths and without color-tuning capabilities. In order to use them for lighting, additional color-conversion material, typically phosphor, is needed. For display applications, multiple chips are required for color-tuning. The highly-strained nature of the InGaN/GaN wells due to lattice and thermal mismatch, especially for those of longer emission wavelengths, offer a viable way of wavelength tuning. Through dimensional downsizing of the emitters, the emission wavelengths can be blue-shifted via the strain-relaxation effect. Such wavelength tuning techniques can be exploited for the development of monolithic broadband LEDs for lighting, as well as RGB pixelated arrays for display applications, potentially offering improvements to performances, as well as manufacturing costs and yields.