Identification and characteristics of core–shell ZnO/ZnO:Mg nanorods synthesized by hydrothermal method

This study successfully synthesized the first core–shell ZnO/Mg doped ZnO (ZnO:Mg) nanorod arrays on p-silicon (100) substrates using the simple hydrothermal method. The vertically aligned synthesized ZnO nanorod arrays served as a template for the growth of 1.75 atomic% Mg doped ZnO. The morphological, structural, and optical features of the nanorod arrays were characterized using microscopic and spectroscopic techniques. The FESEM micrographs showed that diameter of the core is approximately 50 nm encapsulated by shell with thickness of about 30 nm. The low-resolution transmission electron microscopy images showed distinctive morphologies of the core and shell layers. Raman spectroscopy measurements provided structural evidence for the formation of a core–shell ZnO/ZnO:Mg nanorod arrays. The photoluminescence spectra of the core–shell ZnO/ZnO:Mg exhibited an intense sharp peak near-band-edge emission with splitting at 376 and 384 nm, with very weak and negligible defect emission at around 520 nm. Increase in the intensity ratio of the I_UV/I_VIS emission by three confirmed the relatively enhanced optical properties compared with that of core (ZnO) nanorod arrays.