Tailoring the solar-blind photoresponse characteristics of <i>β</i> -Ga <sub>2</sub> O <sub>3</sub> epitaxial films through lattice mismatch and crystal orientation
Jie Yu, Yuehui Wang, Haoran Li, Yuanqi Huang, Weihua Tang, Zhenping Wu
Abstract
Abstract 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, β -Ga 2 O 3 (e.g. ∼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) MgAl 2 O 4 and (0001) α-Al 2 O 3 ), epitaxial β -Ga 2 O 3 films with (100)-or <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mfenced close=")" open="("> <mml:mrow> <mml:mover> <mml:mn>2</mml:mn> <mml:mo>ˉ</mml:mo> </mml:mover> <mml:mn>01</mml:mn> </mml:mrow> </mml:mfenced> </mml:math> -orientation could be fabricated. We found that the photoresponse characteristics are strongly correlated with the lattice mismatch and film orientation. In particular, (100)-oriented β -Ga 2 O 3 film grown on MgO substrate with smaller lattice mismatch exhibited a 254 nm responsivity of 0.1 A · W −1 and detectivity of 4.3 × 10 12 Jones, which are approximately an order of magnitude higher than that of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mfenced close=")" open="("> <mml:mrow> <mml:mover> <mml:mn>2</mml:mn> <mml:mo>ˉ</mml:mo> </mml:mover> <mml:mn>01</mml:mn> </mml:mrow> </mml:mfenced> </mml:math> -oriented β -Ga 2 O 3 film. Our work may provide a strategy to develop further high performance solar-blind photodetectors.