Najeeb Khalid | Two-Photon Research Inc.: What if we could reduce complex MBE calibration from months to days using computational physics?

Can Molecular Beam Epitaxy (MBE) truly double the efficiency of microLEDs and eliminate 14 out of 15 lithography steps?

Najeeb Khalid presents a direct comparison between his company's MBE-grown nano-emitters and conventional MOCVD-grown microLEDs. He claims a significant advantage in internal quantum efficiency (IQE), reporting 40% in blue for their MBE process, compared to the 16-23% typical for commercial MOCVD products. This near-doubling of External Quantum Efficiency (EQE) translates directly to a 50% reduction in power consumption for the final display, a critical factor for mobile and AR applications.

The discussion highlights a major process simplification. While MOCVD requires approximately 15 mask steps to produce the three separate RGB wafers, the nano-emitter approach consolidates this into a single mask step. This is because all colors are grown simultaneously on one wafer. This simplification drastically reduces lithography time and complexity, potentially by an order of magnitude, leading to significant cost and throughput advantages in display manufacturing.

A key differentiator is the ability to cover the entire CIE color space, a feat not achieved by MOCVD which typically covers around 40%. The MBE process can produce any wavelength in the visible spectrum—including challenging greens and reds—in a single step. This capability is the foundation for eliminating the need for mass transfer, as there are no longer separate red, green, and blue chips to be picked and placed onto the display backplane.

In this short video, you can learn:
* How MBE achieves nearly double the External Quantum Efficiency (EQE) of MOCVD.
* The process innovation that reduces lithography mask steps from 15 to just one.
* Why this monolithic, multi-color growth method makes mass transfer obsolete.
📋 **Clip Abstract** This clip details a head-to-head comparison between MBE-grown nano-emitters and traditional MOCVD microLEDs, highlighting significant advantages in efficiency and color gamut. The speaker explains how growing all colors monolithically in a single step drastically simplifies the manufacturing process and eliminates the need for mass transfer.
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Molecular Beam Epitaxy (MBE) has always been a lab tool, not a factory workhorse. What three key breakthroughs were needed to make it commercially viable for display manufacturing?

Najeeb Khalid addresses the historical challenges that have confined Molecular Beam Epitaxy (MBE) to research labs and outlines the innovations required for commercial viability. The first major hurdle is the process's complexity and narrow operating window. To solve this, they developed a proprietary MBE GaN simulator, a software solution that can predict the precise conditions needed for crystal growth, removing the guesswork and variability from the process.

A second critical challenge is the precise measurement of wafer temperature, which must be controlled within ±1°C at temperatures around 900-1000°C. Traditional methods are inadequate and calibrating a machine could take weeks. The company invented a remote, non-contact, high-temperature sensor with 1°C accuracy and repeatability. This tool provides real-time feedback, enabling the tight process control necessary for high-yield manufacturing.

The final bottleneck for throughput was the patterning of the growth mask. Historically, this required expensive and slow Electron Beam Lithography (EBL) for each wafer, taking 2-3 hours and requiring PhD-level operators. They replaced this with a nano-imprinting lithography (NIL) process. This innovation reduces the patterning time to just five minutes per wafer, solving the throughput problem and making the entire front-end process scalable for mass production.

In this short video, you can learn:
* How a software simulator de-risks the complex MBE growth process.
* The invention of a non-contact sensor for precise high-temperature control.
* Why switching from E-Beam Lithography to Nano-Imprinting is key for high throughput.
📋 **Clip Abstract** This segment details the critical engineering solutions developed to overcome the traditional limitations of Molecular Beam Epitaxy (MBE) for mass production. The speaker explains how a unique process simulator, a novel high-accuracy temperature sensor, and a high-throughput nano-imprinting technique make MBE a commercially viable platform for display manufacturing.
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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.
📋 **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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