Defect-engineered monolayer TlBiSe 3 for self-powered polarization detection and reconfigurable spin encoding

Abstract Defect engineering enables precise manipulation of optoelectronic and spintronic properties in two-dimensional (2D) semiconductors. Density functional theory (DFT) calculations reveal that atomic vacancies in monolayer TlBiSe3 induce semiconductor-to-metal transition or semiconductor-to-semimetal transition through band structure reconstruction. In the infrared-visible spectrum (0.1-3.0 eV), defect-engineered monolayer TlBiSe3 exhibits up to 5.3-fold enhanced self-powered photocurrents via the linear photogalvanic effect (PGE) compared to pristine counterparts. This enhancement enables polarization-sensitive detection, with photocurrent exhibits characteristic dependence on polarization angle. Notably, the Se3-vacancy configuration achieves a peak photocurrent density of 3.17 at 1.9 eV, while the Se1-vacancy yields a record extinction ratio of 510.08 at 2.6 eV. Furthermore, Bi vacancy generates near-unity spin-polarized currents ( efficiency) and two-bit reconfigure spin transport channels through photon energy (0.1/0.8 eV) or polarization angle (/) modulation. These findings establish defect-engineered TlBiSe3 as a versatile platform for self-powered polarization detectors and reconfigurable spin encoders.