Solar-Blind UV Photodetector Based on Anisotropic Ga 2 O 3 /MgO Heteroepitaxial Structure for Polarization Imaging

$\beta $-Ga2O3is a promising candidate for solar-blind ultraviolet (UV) polarization detection because of its ultrawide bandgap and low-symmetry monoclinic crystal structure. Herein, an anisotropic$\beta $-Ga2O3(−102)$\vert \vert $MgO (110) heteroepitaxial structure was successfully fabricated via plasma-enhanced chemical vapor deposition (PECVD) method. The film quality and optoelectronic characteristics of$\beta $-Ga2O3(−102) were systematically investigated. Compared with$\beta $-Ga2O3(−201)$\vert \vert $Al2O3(0001) epitaxial structure, the$\beta $-Ga2O3(−102)$\vert \vert $MgO (110)-based UV photodetector (PD) demonstrates superior performance, exhibiting a lower dark current of$3.67\times 10^{\mathbf {-{13}}}$A, a larger photo-to-dark current ratio (PDCR) exceeding$1.23\times 10^{\mathbf {{7}}}$, and a higher responsivity of 114.4 A/W under 254-nm UV light at 5-V bias. Moreover, the polarization sensitivity of the anisotropic$\beta $-Ga2O3(−102) thin films was verified, and its solar-blind UVPD device possessed polarization imaging functionality.