BluGlass awarded US patent for buried activated p-GaN in tunnel junctions

BluGlass Ltd of Silverwater, Australia – which was spun off from the III-nitride department of Macquarie University in 2005 – has been awarded US Patent 10,355,165 (‘Buried Activated p-(Al,In)GaN Layers’) by the United States Patent and Trademark Office. The firm says that the proprietary technology has significant performance potential in applications including high-brightness LEDs, micro-LEDs, laser diodes, solar cells, and other optoelectronic and power electronics devices.

BluGlass says that its remote-plasma chemical vapour deposition (RPCVD)-grown buried activated p-type gallium nitride (p-GaN) layers can help to address the LED industry’s critical challenge of efficiency droop (where the light emission efficiency of an LED falls as operating power is increased), resulting in many existing high-powered LEDs being operated outside their peak efficiency. Incremental efficiency improvements continue to be a major objective for LED makers.

A potential resolution of efficiency droop is multi-junction or cascade devices (LEDs or laser diodes as examples).

BluGlass claims that RPCVD-grown buried activated p-GaN layers are a critical building block to enable the tunnel junction, which in turn allows multiple LEDs to be grown in a continuous vertical stack and interconnected in a single, high-efficiency chip (a cascade LED). As a result, less power is needed to deliver the desired light output, potentially eliminating efficiency droop and significantly increasing device performance.

Cascade LEDs are expected to enable smaller, cheaper and higher-performing LEDs (the LED industry’s three key interests). To date, functioning tunnel junctions – and therefore cascade LEDs – have been prohibitively difficult to produce due to the challenges in achieving buried activated p-GaN using conventional growth technologies such as metal-organic chemical vapour deposition (MOCVD).

BluGlass is developing and commercializing RPCVD technology as an approach to manufacturing group III nitride materials and devices. RPCVD is said to offer better-performing, lower-cost devices and more environmentally sustainable processes for electronics manufacturers producing LEDs for automotive and overhead lighting, micro-LEDs for wearables and virtual reality displays, and power electronics for efficient power conversion.

“This patent adds an important cornerstone to BluGlass’ intellectual property portfolio, protecting our unique RPCVD process, hardware and competitive advantages,” says managing director Giles Bourne. “RPCVD allows us to develop this elegant new option for resolving the challenges of efficiency droop in high-performance LEDs – something that’s been very difficult to resolve using the industry-standard MOCVD technology,” he adds. “Our growing strategic patent portfolio, comprising 63 internationally granted patents, continues to underpin the commercialization of our RPCVD technology across a range of market segments with long-term market exclusivity.”

BluGlass says there has been strong interest in the performance potential of RPCVD tunnel junctions and cascade LEDs from the industry. Discussions with a number of groups are continuing.

See related items:

BluGlass highlights R&D on RPCVD of tunnel junctions at lower temperatures than MOCVD

BluGlass presents latest data on development of RPCVD-grown tunnel junctions for LEDs

BluGlass demonstrates functioning tunnel junctions, enabling cascaded LEDs

Tags: BluGlass RPCVD

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