Regular Article

Theoretical investigation on the EPR parameters for VO²⁺ doped ZnO–CdS nanocomposites

¹ Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang 330063 P.R. China
² Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang 330063 P.R. China

^a e-mail: huamingzhang66@gmail.com

Received: 25 June 2019
Received in final form: 28 October 2019
Published online: 9 January 2020

Abstract

The three optical absorption bands and electron paramagnetic resonance (EPR) parameters g factors (g_||, g_⊥) and the hyperfine structure constants (A_||, A_⊥) for VO²⁺ doped in the ZnO–CdS nanocomposites are theoretically investigated by using the perturbation formulas of these EPR parameters for a 3d¹ ion under tetragonally compressed octahedral based on the cluster approach. In the calculation formulas, the relationships between local structure of the VO²⁺ dopants and the EPR parameters are established from the crystal-field parameters via the tetragonal distortion (characterized by relative tetragonal compression ratio τ), and the contributions to EPR parameters arising from the ligand orbital and spin-orbit coupling interactions via covalence effect are considered. Based on the studies, the V⁴⁺ dopants are found to show a relative compression ratio τ (≈ 2.1%) along the z-axis due to Jahn–Teller effect. Calculated results show reasonable agreement with the experimental data. Reasonableness of the proposed model is discussed.