Influence of Al content on the optical band-gap enhancement and lattice structure of (Ga1-xAlx)2O3 single crystal

Abstract Single crystals of undoped, 4.8, 9.3 and 14.1 at.% Al substituted β-Ga2O3 have been grown by optical floating zone technique. It has been observed that it is not possible to grow good quality single crystal with higher Al content unlike the thin film grown by pulsed laser deposition [Appl. Phys. Lett. 105 (2014) 162107]. It has been found that the incorporation of Al in β-Ga2O3 has resulted a shrinkage in the lattice parameters and volume. This leads to a systematic increase in the band gap of the material and broadens the transmission window in the deep UV range up to 5.08 eV for 14.1 at.% of Al substitution in the lattice.