Effect of annealing treatment on the structural, optical and magnetic properties of ZnSe thin films grown by spray pyrolysis

TL;DR

This study investigates how annealing affects the structural, optical, and magnetic properties of ZnSe thin films grown by spray pyrolysis, revealing enhanced crystallinity, optical shifts, and novel magnetic behaviors.

Contribution

It provides the first comprehensive analysis of magnetic properties of ZnSe nanostructures, including ferromagnetic-antiferromagnetic transition and step-like magnetization behavior.

Findings

Annealing increases grain size and particle density.

UV-vis shows a red-shift in absorption edge after annealing.

Annealed films have a band gap of about 2.71 eV.

Abstract

Many investigations and reviews show that II-VI compound semiconductor 1-D nanostructures have a great potential for the future electronic and optoelectronic applications. As an important II-VI semiconductor, ZnSe is one of the most significant materials with prominent applications in this issue. In the present work, we firstly provide a comprehensive investigation of the magnetic properties like magnetization and magnetic susceptibility of ZnSe nanostructures as a 1-D quantum many body. The magnetic study of this metal reveals a ferromagnetic-antifferomagnetic transition upon cooling. Magnetization shows a step-like behavior with pronounced plateaus in a specific magnetic field interval at low temperature. This subject has not been investigated in the previous works. In the experimental part, thin films of ZnSe are deposited on glass substrates (at two different substrate temperature) by the spray pyrolysis technique and annealed in vacuum at $400^\circ$C for 1 hour. Hereby, we investigate the morphology, structural and optical properties of ZnSe thin films using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) and UV-vis spectrophotometer measurements. XRD analysis reveal that annealed films grown on glass substrate at $400^\circ$C are polycrystalline in nature with cubic zincblene structure. By annealing, the grains size, the diameter and density of the particles increase. The UV-vis measurements display a red-shift of the absorption edge from the as-deposited to annealed ZnSe thin films as compared to its value for the ZnSe thin films. The band-gaps of the annealed samples are estimated about 2.71 eV, which are in consistence with the band gap of ZnSe thin films. The average transmittance of the annealed samples are over 80 $\%$ close to the infrared wavelength range.