Tailoring the solar-blind photoresponse characteristics of β-Ga2O3 epitaxial films through lattice mismatch and crystal orientation

Realizing manipulation of the photoelectric properties of wide bandgap semiconductors is a main challenge for successful next-generation functional optoelectronics. As an intriguing wide bandgap semiconductor, beta-Ga2O3 (e.g. similar to 4.9 eV) is emerging as a promising candidate for photodetectors operating in the solar-blind region. Here, we show that by selecting substrates with different symmetries and lattice parameters (i.e. (100) MgO, (100) MgAl2O4 and (0001) alpha-Al2O3), epitaxial beta-Ga2O3 films with (100)-or -orientation could be fabricated. We found that the photoresponse characteristics are strongly correlated with the lattice mismatch and film orientation. In particular, (100)-oriented beta-Ga2O3 film grown on MgO substrate with smaller lattice mismatch exhibited a 254 nm responsivity of 0.1 A center dot W-1 and detectivity of 4.3 x 10(12) Jones, which are approximately an order of magnitude higher than that of the x2c9;01 beta-Ga2O3 film. Our work may provide a strategy to develop further high performance solar-blind photodetectors.