High Aspect Ratio AlN Nanowires for efficient deep UV emission – HARAlN

Light sources emitting intensely in the deep UV (UVC <280nm) are highly sought after in the medical and sanitary fields, due to their bactericidal action which allows, among other things, the sterilization of surfaces or the treatment of water at low cost. Nitride semiconductor (SC III-N) light-emitting diodes (LEDs) are a promising alternative to mercury vapor lamps for making compact and environmentally friendly UVC sources. However, today they are not achieving the expected emission efficiencies. It has been shown that a 3D rather than planar architecture of SC III-N-based sources allows increased emission efficiencies. To reach the UVC, it is then necessary to be able to structure the AlN into organized networks of nanowires with a high aspect ratio (AR> 10, diameter ~250nm) on which quantum wells of AlGaN rich in Al (>50%) are grown radially in core/shell geometry . Unfortunately, the existing processes involved in the fabrication of this core (AlN) / shell (AlGaN/AlN) architecture show limitations. Thus, the HARAlN project aims to fabricate AlN nanowire sources emitting in the deep UVC with efficiencies surpassing planar approaches by providing innovative manufacturing processes transferable to industry. We want to demonstrate:
- the potential of advanced pulsed plasma technologies to pattern materials with high aspect ratio, and more particularly AlN nanowire.
- the growth of emissive structures in UV C (Alx>50%GaN or GaN monolayer in AlN barriers) on the vertical m-planes of AlN wires by MOPVE (Metal Organic Vapor Phase Epitaxy)
Beyond this technological objective which would provide industrial solutions for increasing the efficiency of UVC LEDs, this project is an exceptional opportunity to produce new knowledge in the fields of plasma etching processes, and the growth of III-N semiconductors by MOPVE in core-shell architecture.