Startup Porotech debuts native red LED epiwafer for micro-LEDs

24 Nov 2020

University of Cambridge spin-out claims “first” such wafer based on gallium nitride production method.

University of Cambridge spin-out Porotech has launched the first product based on its new gallium nitride (GaN) production technique, which it says will “transform the electronics industry.” The company describes this as “the first commercial native red LED epiwafer for micro-LED applications.”

Micro-LED display technology offers a huge improvement on standard display panels due to its optimum brightness, efficiency and image definition, as well as improved lifetime. These benefits are crucial for near-to-eye applications such as augmented reality (AR) and head-mounted displays – a market predicted to be worth tens of billions of dollars over the next five years.

They are also required for a range of other applications – from large area displays and TVs to mobile phones and wearable devices such as smartwatches. But, until now, achieving the necessary high-efficiency, ultra-fine-pitch red pixels has proved a challenge, says Porotech.

Conventional red LEDs are largely based on aluminum indium gallium phosphide (AlInGaP) materials. This means they exhibit a significant efficiency drop as the device size decreases due to their large carrier diffusion lengths and high surface recombination velocity, explains the company.

New class of GaN materials

Porotech’s production process has enabled the creation of a new class of porous GaN semiconductor materials. As a result, the company claims to be the first to launch a commercially available native red indium gallium nitride (InGaN) LED epiwafer for micro-LED applications.

“Micro-LED displays using GaN-based material technology are widely seen as the only technology that can deliver displays bright and efficient enough to meet the requirements of AR,” commented Porotech CEO and co-founder Dr Tongtong Zhu. “With AR glasses expected to one day replace smartphones – or at least reduce our interaction with the devices in our pockets – development of advanced materials to improve performance is crucial.

“Integration of AlInGaP red and indium InGaN green and blue LED displays in a module with micron-scale pixels is extremely challenging as high surface recombination velocities in AlInGaP devices make this material unsuitable for efficient micro-LEDs. Our breakthrough extends the emission range of InGaN LEDs to meet the performance needs of the red display, whilst delivering the ability to scale wafer size required by micro-LED semiconductor display technology.”

GaN is a material poised to make an impact across electronics and optoelectronics – from efficient power transistors and lasers to quantum devices, sensors and solar cells – and the introduction of porous architectures can extend its capability in all these realms. Porotech's product fits within existing industry standards and processes.

The proprietary technology is robust but also flexible enough to be tailored to the needs of different applications. Porotech’s native red InGaN micro-LEDs have a wavelength of 640 nm at 10 A/cm2, and improved performance over conventional AlInGaP and colour-converted red at very small pixels and pitches.

Earlier in 2020, Porotech secured a £1.5 million seed round investment co-led by Cambridge Enterprise, the commercialisation arm of the University of Cambridge, and IQ Capital Partners, with the additional participation of Martlet Capital and a syndicate of angel investors from Cambridge Angels and Cambridge Capital Group.