Top-down fabrication of InGaN-based nano light-emitting diodes

Micro/Nano light emitting diodes (LEDs) have become front-runners for next-generation display architectures compared to organic LED (OLED) and liquid crystal displays in part due to their superior performance. Their versatility has led to additional applications in visible light communications (VLC), sensing and optogenetics. Despite potential benefits of smaller devices, there have been limited efforts in demonstrating sub-micron LEDs due to challenges in scaling fabrication techniques from large area LEDs. In this work, first, we demonstrate a top-down fabrication process using electron beam lithography where nano-LEDs with mesa sizes down to 250nm were fabricated. Then, the optical properties of the nano- LEDs are studied. Spectral properties as a function of injection current density from 1.6Acm^-2 to 240Acm^-2were measured showing minimum variation in FWHM of approximately 20nm and invariant peak wavelength of approximately 439nm from 24Acm^-2 to 240Acm^-2. Spatially resolved optical properties were studied via micro-electroluminescence mapping and confocal microscopy demonstrating sub-micron spatial emission profile width of approximately 800 nm. This work shows the potential of nano LEDs as a suitable technology for next generation displays and advanced light engines.