There's two sides to gallium nitride-based semiconductors, and many simultaneous functions

https://techxplore.com/news/2024-09-sides-semiconductor-simultaneous-functions.html

"combines: (1) nitrogen side: high-frequency, power (electronics). (2) gallium side: energy-efficient LED lighting (photonics), (3) potentially acoustics), enabling smaller, cheaper, more energy efficient devices... large electronic polarization along its crystal axis, so different physical/ chemical properties per surface... grow transparent GaN substrates on single crystal wafer 400 µm thick... devices do not degrade... driving a large LED, turning it on and off at kilohertz frequencies—plenty for a working LED display"