Investigation on microstructure, energy gap, photoluminescence and magnetic studies of Co and Cu in situ doped ZnO nanostructures

Co (3%)-doped ZnO and Co, Cu (Co = 3% 2 to 4%) dual-doped nanostructures were prepared using chemical co-precipitation route. The structural analysis indicated no alteration in the structure of hexagonal absence secondary/impurity phases induced by Co/Cu addition into ZnO. reduction crystallite size (≈ 25 nm) at 2% is due suppression growth rate dissimilarities between Co2+/Cu2+ Zn2+ ions, enhanced 29 4% responsible for more defect sites associated with interstitials vacancies Co2+ Cu2+ Zn–O lattice. persistent c/a ratio (~ 1.602) signified modification substitution Zn. decrease optical absorption, increase transmittance energy gap discussed consideration dopants stimulated states. continuous widening (ΔEg ≈ 0.08 eV) clarified Burstein–Moss (BM) band filling effect through energy-level diagram. existence Zn–Co/Cu–O bondings around 442–468 cm−1 was verified Fourier transform infra-red analysis. elevated intensity green ultra-violet photoluminescence (IG/IUV) higher concentration, 0.74), revealed occurrence number defects, particularly oxygen-related states, (Zn, Cu)O observed room temperature ferromagnetism (RTFM) Cu-doped based on oxygen vacancy-mediated bound magnetic polarons (BMP) exchange interaction free electrons local spin-polarized electrons.