BAlGaN alloys nearly lattice-matched to AlN for efficient UV LEDs

The lattice mismatch between AlGaN and AlN substrates limits the design and efficiency of UV LEDs, but it can be mitigated by the co-incorporation of boron. We employ hybrid density functional theory to investigate the thermodynamic, structural, and electronic properties of BAlGaN alloys. We show that BAlGaN can lattice match AlN with band gaps that match AlGaN of the same gallium content. We predict that BAlGaN emits transverse-electric polarized for gallium content of ~45% or more. Our results indicate that BAlGaN alloys are promising materials for higher efficiency UV optoelectronic devices on bulk AlN substrates.