Monolithic Multi-Color Tunable Inorganic Light-Emitting Diodes

Inorganic light-emitting diodes (LEDs) possess exceptional advantages for achieving wide wavelength emission ranges. However, certain material limitations should be overcome to alleviate the green gap between InGaN and AlInGaP-based LEDs. In this study, monolithic red, green, and bluish-green emissions are achieved by exploiting the blueshift phenomenon, caused by the band-filling and piezoelectric screening effects. Different-sized LEDs are designed to control the injection current density on the same wafer. The smaller the size of the LED, the shorter the emission wavelength, resulting in multi-color emission (from red to bluish-green). As a result, red, green, and white emissions are individually and simultaneously obtained using dichromatic LED systems, comprising three red and one green LED cell. In addition, a wide range of visible light colors are achieved by adjusting the size of the LEDs and the applies injection current.