Capturedcharged

Capturedcharged is a term used in materials science to describe a localized, charged state in which a free charge carrier (electron or hole) becomes trapped at a defect or impurity within a solid. The term reflects the combination of the capture event and the resulting stationary charge, in contrast to free carriers that move through the material.

Mechanism and energetics: Trapping occurs at defect states within the band gap or at shallow surfaces, with a capture cross-section, and occupancy depends on the Fermi level and temperature. A captured charge is typically tied to a defect site and may be released thermally or via optical excitation, returning to the conduction or valence band. The capturedcharged state can be short-lived or long-lived, depending on trap depth and the local environment.

Implications in materials and devices: The presence of captured charges reduces free carrier density and mobility, alters recombination dynamics, and can give rise to persistent photoconductivity or spectral response changes. In semiconductors and photovoltaics, trap-related capture affects minority-carrier lifetimes, diffusion lengths, and device performance. In ionic crystals or organic semiconductors, similar trap states influence dielectric behavior and charge transport.

Relation to related concepts: The concept overlaps with trap states, defect levels, and charge localization. It is often discussed alongside 'traps,' 'deep-level defects,' and 'charge trapping' in the literature. The exact usage of 'capturedcharged' varies and is not universally adopted; some authors prefer more conventional terminology.