First-principles calculations of BAlGaN alloys nearly latticed matched to AlN for deep UV light emission*

With the great success of InGaN LEDs visible light production, deep UV LEDs based on AlGaN have also been the subject of intense research activity. However, material issues still hamper the manufacturing of deep UV LEDs with efficiencies matching those of InGaN-based visible LEDs. Of note are the difficulty of traditional hole injection into p-AlGaN and the UV absorption in p-GaN often used in place of p-AlGaN. We used hybrid density functional theory to analyze the electronic, structural, and thermodynamic properties of BAlGaN alloys nearly latticed matched to AlN as potential new materials for deep UV LED design. We show that boron incorporation into AlGaN allows for improved lattice matching to AlN with only a small effect on the band gap. The a lattice parameter is more sensitive to boron incorporation than the c lattice parameter. We predict similar boron incorporation limits (~15% boron) as in BAlN, but with easier incorporation of low boron content than in BAlN due to increased configurational entropy.