Ultrasensitive polarization-dependent ultraviolet detection enabled by electrical and optical anisotropies

Abstract

The detection of multi-dimensional parameters such as polarization, light intensity, and wavelength represents a significant leap forward in the development of high-performance photodetectors. However, the growing functional demands place increasingly stringent requirements on both materials and devices. In this study, we introduce a PdTe2/GaN heterostructure ultraviolet (UV) polarization-sensitive photodetector integrating telluride and nitride materials. We systematically investigate the intrinsic carrier mobility discrepancy of diverse materials and validate the significant electrical anisotropy of PdTe2 through deformation potential theory. Additionally, polarized Raman spectroscopy reveals distinct vibrational modes in PdTe2 along the a- and b-axes, underscoring its remarkable optical anisotropy. The synergistic electrical and optical anisotropies within the PdTe2/GaN heterostructure result in an impressive dichroic ratio of 37.23 for the photodetector under 365 nm polarized light, far exceeding previously reported results in UV polarization detection. The device also demonstrates an ultrafast response time of 3.12 μs and a high specific detectivity of 2.2 × 1013 Jones at −5 V. Single-pixel polarization imaging further confirms the device's exceptional polarization detection performance. These findings not only present an effective approach to the development of multi-dimensional photodetection systems but also establish a robust theoretical framework for advancing device-oriented explorations.