Hexagem is a company that has its roots in Lund University and IP developed for a company called Glo. Nanosys acquired Glo in 2021 and then sold the facility to Avicena in 2022. Avicena is active in developing microLEDs for the Datacom application.

One big challenge is to reduce lattice mismatch between GaN epi layers and a supporting substrate. This is particularly acute for GaN red microLEDs which incorporate a lot of Indium. In paper 112-1, Lars Samuelson, Professor at Lund University explained that they start their bottom up growth on a “relaxed InGaN substrate” that incorporates 20% Indium. This allows the company to now grow sub-micron sized “platelet” structures for red, green and blue emitters with the difficult red microLEDs achieving an impressive 50% internal quantum efficiency (IQE).

Lund says that once the GaN seeds are formed with a MOVPE process, MOCVD processing is used to grow the quantum wells. Red, green and blue platelets (truncated hexagons) need different concentrations of In and Ga so currently, the company only grows a single color on the substrate, but they hope to demonstrate all three colors on a single substrate in the future.

This work remains in an early stage, but they recently received a 3.4M Euro contract to develop methods for contacting their nanoLEDs to a 200mm CMOS backplane.