Anisotropic performances and bending stress effects of the flexible solar-blind photodetectors based on β-Ga2O3 (1 0 0) surface

Flexible β-gallium oxide (β-Ga2O3) crystal microstrips were fabricated by mechanical exfoliation of the bulk single crystal. The polarized Raman spectra of the β-Ga2O3 (1 0 0) surface illustrate anisotropic vibration. Flexible solar-blind photodetectors (SBPDs) based on the β-Ga2O3 strips were fabricated with channels in various orientations on (1 0 0) surface, showing clear anisotropic photoresponses. The SBPD with the channel orientation at ∼ 60° to [0 1 0] realizes the highest photocurrent with the high responsivity of 15.40 A/W, high external quantum efficiency of 7.65 × 103%, high detectivity of 9.81 × 1011 Jones, and fast response rise/decay time of 0.31/0.05 s, indicating the most effective carrier transport along this orientation. Under the bending stress, the crystal structure is distorted revealed by the X-ray diffraction, and the Raman spectroscopy results proved that the lattice vibration is modified. The photocurrent of the SBPDs with anisotropic channel orientations increases with the increased bending stress, due to the increased photo absorption and photo carrier generating caused by the stretched lattice structure. These results should give significant guidance to the construction and application of high performance electronics and photoelectronics based on β-Ga2O3 (1 0 0) surface.