In-situ fabrication of GaN/short-range ordered BN heterostructure light-emitting diodes

Abstract

We fabricated GaN/BN double heterostructure light-emitting diodes (LEDs) where the BN layer exhibited an amorphous-like short-range order and facilitated the in-situ epitaxial lateral overgrowth (ELOG) of GaN films. Using an identical metal-organic chemical vapor deposition, the BN layer was reliably formed on the GaN film and then served as a growth mask during the high-temperature growth of the GaN overlayer. The BN layers were well dispersed over the entire surface with a partial coverage of 40-60% and a thickness of a few nm. The laterally overgrown GaN was epitaxially related to the initial GaN film exhibiting single crystallinity with flat and smooth surface morphology. Meanwhile, the in-situ-formed BN layer effectively blocked the threading dislocations where its density reductions were comparable to those of typical ex-situ ELOG processes. Furthermore, the BN-assisted ELOG reduced the mosaic of the practical single crystalline GaN grains and drastically improved crystallographic alignment and internal quantum efficiency. More importantly, the BN-assisted ELOG yielded high device performance of the GaN LEDs demonstrating that the benefits of ELOG were fully achieved with the fast and instant fabrication process.