Monolithic cyan − violet InGaN/GaN LED array

Abstract

In the case of InGaN alloys grown by metalorganic vapour phase epitaxy on a c‐plane GaN, indium content decreases as the substrate miscut is increased. This phenomenon has been previously used to fabricate laser diodes with variable wavelength on one chip [Appl. Phys. Express 5, 021001 (2012)]. In that work, however, wavelength variation was only 5 nm. In the present work we show independent, electrically driven array of light emitting diodes (LED), covering 40 nm emission wavelength range on one chip. This is achieved by a particular patterning technique, which enables the change in the local miscut of the substrate by introducing large enough slopes for practical devices. This technological approach offers a new degree of freedom for InGaN/GaN bandgap modification and device engineering. It can be applied to freestanding GaN as well as to GaN/sapphire templates used for mass production of LEDs. Once optimized, this approach could eventually lead to truly monolithic RGB LEDs.

Multiwavelength-emitting InGaN quantum wells on convex-lens-shaped GaN microstructures

“…This finding is consistent with previous reports. [26][27][28]34) Additionally, the wider wavelength shift mentioned above is attributed to the larger In composition variation (>10%) compared to that (4.5%) of the previous report. 27) This is most likely due to the larger maximum offangle.…”

“…InGaN-based multiwavelength light emitters utilizing local off-angle variation have already been demonstrated. [24][25][26][27][28] Dróżdż et al fabricated InGaN LEDs on (0001) GaN surfaces with several hundreds of μm-scale patterns formed by grayscale photolithography and dry etching. 27) The local offangle ranges from 0.3 to 2.4°.…”

“…[24][25][26][27][28] Dróżdż et al fabricated InGaN LEDs on (0001) GaN surfaces with several hundreds of μm-scale patterns formed by grayscale photolithography and dry etching. 27) The local offangle ranges from 0.3 to 2.4°. As the off-angle increases, the In composition decreases, and the corresponding emission wavelength of the InGaN QWs shifts from 480 nm to 440 nm.…”

“…The ∼90 nm shift is wider than that (40 nm) in the previous report. 27) The reason is discussed in the following QW structure analyses. Here, it should be noted that the wide wavelength shift is achieved within the shallow off-angle range [Fig.…”

Indium Incorporation into InGaN Quantum Wells Grown on GaN Narrow Stripes

“…In one of our previous papers [26] we reported on InGaN quantum wells grown on stripes with various off-cuts. As indium incorporation into InGaN depends on the off-cut [27], by varying the off-cut spatially we could produce monolithically integrated multicolor emitters.…”