Najeeb Khalid | Two Photon Research Inc.: How can you grow red, green, and blue GaN emitters simultaneously in one process by just changing the diameter of a nanorod?
16:13 - 18:27
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How can you grow red, green, and blue GaN emitters simultaneously in one process by just changing the diameter of a nanorod?
Najeeb Khalid explains the physics behind growing multiple colors in a single Molecular Beam Epitaxy (MBE) process step, a core innovation that eliminates the need for separate RGB wafers. The mechanism relies on controlling the diffusion length of atoms impinging on the wafer surface. The key insight is that the travel distance for atoms from the base of the wafer to the quantum well at the top of a nano-emitter changes with the emitter's diameter.
The color is determined by the concentration of Indium in the Indium Gallium Nitride (InGaN) quantum well. The process leverages the differential diffusion of Indium atoms versus Gallium atoms on the surface. Because the travel path to the quantum well is longer on wider-diameter nano-emitters and shorter on narrower ones, the final concentration of Indium incorporated into the quantum well varies systematically with the emitter's geometry.
This relationship is predictable and controllable: smaller diameter emitters (e.g., 60-80 nm) incorporate more Indium, shifting the emission towards red, while larger diameter emitters (e.g., 400-500 nm) incorporate less Indium, resulting in blue emission. By pre-patterning a single mask with holes of varying diameters, one can precisely define the location of every red, green, and blue subpixel on the wafer. The entire color palette is thus encoded in the initial lithography pattern, with the subsequent MBE growth step executing this color plan simultaneously across the wafer.
In this short video, you can learn:
* The role of atomic diffusion length in determining InGaN composition.
* How nano-emitter diameter directly controls the incorporation of Indium to tune color.
* The method of using a single patterned mask to define a full-color display layout.
π **Clip Abstract** The speaker reveals the core physics behind their single-step, multi-color growth process. He explains how varying the diameter of the nano-emitters alters the diffusion path for Indium atoms, thereby controlling the InGaN composition and emission wavelength without needing separate growth runs or masks for RGB.
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#GaNNanorodRGB, #MBEGrowth, #IndiumDiffusionControl, #InGaNComposition, #MicroLEDDisplays, #ARDisplayTech
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Can going 1,000x smaller solve the existential efficiency droop of micro-LEDs?
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