Deposition of In and Al Doped Zno Thin Films by Spray Pyrolysis Technique and Their Characterization

Abstract

This thesis focused on developing undoped, In-doped, and Al-doped ZnO thin films by spray pyrolysis at optimized deposition parameters and investigating their structural, morphological, optical, and gas-sensing properties. The goals of the work embodied in this thesis are divided into five chapters. Chapter 1 is a complete discussion on metal oxide semiconductors (MOS) thin films, zinc oxides (ZnO), defects in ZnO, a review of group III doped ZnO thin films, motivation and objectives of the present research work. newlineChapter 2 provides an overview of commonly used deposition and processing methods, followed by a discussion of the different characterization techniques used in the present study. newlineChapter 3 provides a complete investigation of In-doped ZnO thin films synthesized using a spray pyrolysis method with optimized deposition parameters. Thin films of undoped and In-doped ZnO were deposited on clean glass substrates using spray pyrolysis method. The films were deposited at substrate temperature 400 and#8451;. The dopant concentration of indium was varied from 0 to 5%. The structural, optical, morphological, and optical properties have been studied before and after the incorporation of In. The structural studies of the samples were analyzed using X-ray diffraction (XRD) technique. All the XRD patterns of the films showed a polycrystalline phase and have hexagonal (wurtzite) crystal structure. The preferred is shifted from (002) to (101) with In-doping concentration. The lattice parameters and volume of unit cell of In-doped ZnO films showed increasing trend suggested incorporation of In ions into ZnO crystal lattices. Average crystallite size was found to be decreases from 53.40 nm to 32.84 nm as In-doping concentration increases. Field emission scanning electron microscope (FESEM) show that the nanoroads like morphology of undoped film transferred into spherically distributed nanoparticles upon In-doping into ZnO. Energy dispersive spectroscopy (EDS) analysis confirm an enhancement in the amount of In in the film with i