Defect model of a Cu2+ center in CdSe nanocrystals

• Published in: Physica. B, Condensed matter Vol. 430; pp. 84 - 86
• Main Author: Li, Bang-Xing
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.12.2013; Elsevier
• Subjects: Cadmium selenides; CdSe nanocrystal; Clusters; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Crystal- and ligand-field theory; Cu2; Defect model; Defects; Electron paramagnetic resonance and relaxation; Exact sciences and technology; Intermetallics; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Mathematical models; Nanocrystals; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Perturbation methods; Physics; Spin-Hamiltonian parameters; Symmetry; Cu2; CdSe nanocrystal; Defect model; Crystal- and ligand-field theory; Spin-Hamiltonian parameters; Perturbation theory; Interstitials; Copper additions; Crystal field; Cluster model; Defects; Cadmium selenides; Cu; Substitutional impurities; Spin Hamiltonians; Crystallographic site; Electron paramagnetic resonance; Absorption spectra; Nanocrystal
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2013.08.034

By using the defect model of Cu2+ at the substitutional tetrahedral site with tetragonal symmetry, the spin-Hamiltonian parameters g//, g⊥, A// and A⊥ of a Cu2+ center in CdSe nanocrystals are calculated from the high-order perturbation formulas based on the cluster approach. The calculated results are in reasonable agreement with the experimental values. However, in a previous paper, these spin-Hamiltonian parameters were also explained from the high-order perturbation formulas based on the cluster approach by using another defect model of the Cu2+ ion at the interstitial octahedral site with tetragonal symmetry in CdSe nanocrystals. So it may be impossible to determine the defect model of the Cu2+ center in CdSe nanocrystals by analyzing only the spin-Hamiltonian parameters obtained from EPR spectra. A possible method of absorption spectra in the range 4000–15,000cm−1 is suggested to determine the defect model of the Cu2+ center in CdSe nanocrystals.