Research Information System
MICRO AND NANOSTRUCTURES, vol.209, 2026 (SCI-Expanded, Scopus)
Polycrystalline CuIn4Se7, CuInZnSe3, and CuInFe2Se5 chalcogenide semiconductors were synthesized by a solid-state reaction and systematically studied using positron annihilation lifetime spectroscopy (PALS) and Doppler broadening annihilation spectroscopy (DBAS). Depth-resolved S-W analysis revealed distinct dopant-dependent defect distributions: Zn incorporation led to a higher concentration of small, homogeneously distributed vacancies, while Fe doping enhanced positron trapping through increased d-p hybridization and promoted the aggregation of fewer but larger vacancy clusters. PALS measurements identified two dominant lifetime components (tau 1 = 265-274 ps, tau 2 = 372-401 ps), with Zn-doped samples showing intermediate behavior between undoped CuIn4Se7 and Fe-doped CuInFe2Se5. Electron momentum distribution (EMD) spectra further confirmed that Zn favors annihilation with s-p type electrons, whereas Fe increases the contribution of d-orbital electrons, broadening the central momentum peak. The direct correlation between PALS and EMD results establishes that the cation d-orbital configuration governs both the geometric size and the electronic character of vacancy-type defects. These insights provide a fundamental framework for defect engineering in Cu-In-Se chalcogenides, where Zn doping may be advantageous for photovoltaic applications requiring minimized recombination, while Fe doping could enhance thermoelectric performance via phonon scattering from larger vacancy clusters.