Study of Electrical and Optical Properties of Iron Doped Zinc Oxide Thin Films Grown by Spin Coating Method for Optoelectronic Device

Abstract

In this study the effect of iron doping on zinc oxide nanoparticles was investigated for optoelectronic application. Zinc oxide thin films were grown on microscopic glass slides using spin coater by varying the iron concentration by 1%, 3%, 5% and 10% and calcinating all the samples at 500 0 c for 2 hours. The XRD analysis showed the formation of polycrystalline zinc oxide thin films with hexagonal wurtzite structure. The lattice constants and grain size were observed to decrease while the lattice defects increased up on increasing the iron concentration. Optical analysis done using UV-Vis and photoluminescence spectroscopy revealed enhanced visible light absoption and emission behavior of the doped ZnO thin films compared to the undoped ZnO thin film. The energy band gap also decreased from 3.29 eV for the undoped thin film to 3.25 eV for 3% iron doped thin film. Increased iron concentration beyond 3% was observed to impart blue light absorption ability to the thin films due to increased effect of deep levels of the oxygen vacancies. The emission spectra of the samples were observed to red shift revealing non-radiative energy loses due to lattice vibration. The Hall measurement results indicated that all films had good electron conductivity and mobility which make them useful for optoelectronic devices. Considering the results from all measurement, the thin film with 3% iron was found to be optimal for optoelectronic application due to its relatively lower defects, visible light absorption as well as good electron conductivity and mobility