Strain-enhanced polarization sensitivity inβ-Ga_(2)O_(3)photodetector

Polarization-sensitive photodetection and imaging have great application value in fields such as polarization division multiplexing optical communication,remote sensing,near-field imaging and military monitoring.Pursuing a high polarization ratio has always been the research hotspot in polarization-sensitive photodetectors.In this paper,we report a compression strain enhanced polarization ratio inβ-gallium oxide(β-Ga_(2)O_(3))single crystal flake.A rigorous crystallographic analysis confirmed its high crystalline quality and orientation.Angle-resolved polarization Raman spectroscopy(ARPRS)was adopted to study the anisotropy of its optical properties.Extensive ARPRS measurements and theoretical calculation consistently demonstrate the strong optical anisotropy in the high-qualityβ-Ga_(2)O_(3)flake.A polarization ratio of 0.96 was obtained in the flatβ-Ga_(2)O_(3)flake.Furthermore,mechanical strain of±0.7%was introduced intoβ-Ga_(2)O_(3).An increased polarization ratio of 0.98 was achieved in the case of 0.7%compression strain,which is,to the best of our knowledge,the highest value for UVC polarization-sensitive photodetectors.That corresponds to an improved polarization rejection ratio of 100.This work proposed a new path towards improving polarization sensitivity by applying strain engineering in the active material.