Polarization Detection of Deep-ultraviolet Light with Monoclinic Gallium Oxide Nanobelts
Detection of polarization in deep-ultraviolet (DUV) wavelength is of great importance, especially in secure UV communication. In this paper, we report DUV polarization detectors based on ultra-wide bandgap β-Ga2O3 nanobelts, which belong to monoclinic system with strong anisotropic lattice structure. The single-crystalline β-Ga2O3 nanobelts are synthesized at high-temperature via chemical vapor deposition (CVD). Crystallographic investigation is performed to determine the crystal orientation of the nanobelts, by the combination of selected area electron diffraction (SAED), high-resolution transmission electron microscope (HRTEM), crystal modeling and diffraction simulation. Photoresponse to unpolarized DUV light shows high responsivity of 335 AW-1 and high sensitivity even to low illumination power of pW. Strong anisotropy in responsivity and response speed, depending on incident light polarization, is observed. The underlying mechanism is attributed to the combination of internal dichroism and 1D morphology, as the DFT calculation and FDTD simulaiton indicate. This work shows a way of DUV polarization detection using CVD grown Ga2O3 nanobelts, which could broaden the investigation of Ga2O3 materials and DUV photodetection.