Project aims for ultimate micro-displays

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A new way of making micro-displays for next-generation smartphones, smartwatches and VR headsets is being developed in an EPSRC-funded project led by Sheffield University.

micro-displays
One of the device characterisation and testing facilities in the photoluminescence and electroluminescence laboratories at Sheffield University (Image: Sheffield University)

In a new project led by Professor Tao Wang from the University’s Department of Electronic and Electrical Engineering, in collaboration with Harvard and MIT, researchers are using micro laser diodes - microLDs - to develop ultimate micro-display and visible light communication devices.

Micro-displays are currently used in smartphones, smartwatches, augmented reality and virtual reality devices. According to the University, visible light communication technology could offer much greater bandwidth and efficiency than WiFi or 5G and can be used where radio frequency emissions are controlled or do not work such as in aircraft, hospitals, underwater and hazardous environments.

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A key component of both these technologies are III-nitride visible light-emitting diodes (LEDs) but using laser diodes (LDs) instead has the potential to achieve devices with even higher resolution, speed and efficiency.

In the £1.9m project, the Sheffield-led team is developing an innovative new way of integrating microscale semiconductor light sources and transistors on a single chip.

“The significantly increasing demands on micro displays are pushing the requirements for ultra-high resolution and ultra-high efficiency,” Prof Tao Wang said in a statement. “Several fundamental challenges with fabrication and electrical driving methods cannot be met by existing technologies therefore a disruptive technology needs to be developed. Unlike any existing photonics and electronics fabrication approaches, our research will explore a completely different approach to monolithically integrate microscale laser diodes [μLDs] and high electron mobility transistors [HEMTs] on a single chip, where each μLD is electrically driven by individual HEMTs.”

The global micro-display market is predicted to reach $4.2bn by 2025 and the visible light communication market is expected to exceed $8bn by 2030. The Sheffield-led project is already being supported by global tech companies including Microsoft, Sony and Plessey.