Radiative Defects in Chloride-Activated CdSe Thin Films.

ABSTRACT: Defect recombination limits wide-gap Se-based chalcogenide devices, yet how chloride activation reshapes radiative pathways remains unclear. Here we show that a 40 min CdCl₂ anneal converts evaporated CdSe from porous nanograins into dense micrometer-scale polycrystals and sharpens the optical band edge, reducing the Urbach energy from 85 to 17 meV at 300 K. Combining temperature- and fluence-dependent photoluminescence (PL), time-resolved PL, hyperspectral mapping, and hybrid-DFT, we resolve three emissive channels and identify their mechanisms. The near-edge band is excitonic at low temperature and evolves into free-carrier emission at elevated temperature. A sub-gap band at E _g -0.45 eV requires above-gap carriers and thermally quenches with a 0.16 eV

SUBMITTER: Abudulimu A 

PROVIDER: S-EPMC12910657 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature