Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-020-04046-7 Characterization of MgO thin flm prepared by spray pyrolysis technique using perfume atomizer S. Visweswaran 1  · R. Venkatachalapathy 1  · M. Haris 2  · R. Murugesan 3 Received: 2 March 2020 / Accepted: 18 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Transparent conducting magnesium oxide (MgO) thin flms are obtained by pyrolytic decomposition of magnesium acetate in a mixture of ethanol and distilled water on to a glass substrate using perfume atomizer. The substrate temperature (T s ) is maintained at 300 °C, 350 °C, 400 °C, and 450 °C for depositing the flms and annealed at 450 °C for 4 h. Then the samples were characterized by X-ray difraction, feld emission scanning electron microscope, atomic force microscope, UV–Vis spec- troscopy, photoluminescence analyzer, and Raman spectrophotometer for identifying its structure, morphology, topography, bandgap and defect states. The XRD result demonstrates the cubic, polycrystalline nature with (2 0 0) preferred orientation. The presence of MgO 2 phase along (2 2 2) plane increases with substrate temperature is noticed. From the SEM monograph, the clusters of spherical grains are observed for all the flms and the columnar growth of the MgO flm is observed from the AFM topographical image. The surface roughness tends to increase with substrate temperature. The MgO thin flms possess two absorption bands and two optical bandgaps. The transmittance of 70% is obtained for MgO flm which could be used for optoelectronic device and protective coating applications. The blue and green emission bands are identifed from the PL spectrum. The defects in the flm are responsible for linear I–V characteristic and the large forward current value implies higher efciency for solar cell applications. 1 Introduction Magnesium oxide (MgO) thin flms have a signifcant role in optoelectronic devices, light-emitting diodes, piezoelec- tric devices, photodetectors, sensors and solar cells, plasma panels, smart and wearable devices, electrochromic device, wastewater treatment, drug delivery, and health care industry [1–8]. MgO is an ionic solid known as halite, in cubic rock salt form. It consists of two oxygen anion and metal cation interpenetrating the FCC sublattice [9]. Transparent con- ducting oxide (TCO) having high optical transparency and electrical conductivity is the advantage of MgO thin flm. Its properties include wide bandgap energy (7.8 eV), die- lectric constant (6.8), thermal conductivity (42 Wm −1 K −1 ), hardness (5000 MPa), and elevated melting temperature [10]. In general, three types of vacancies are found for MgO identifed as F s , F s + , F s 2+ (color centers) depending on the number of electrons trapped found from PL analysis [11]. Due to its signifcant variation in size and morphological dimensions or structures nanowires [12], microtubes [13], nanorods [14], sheets, fakes, nanofowers [15], needles are obtained from various deposition methods such as vac- uum arc difusion [16], spin-coating [12] dip-coating, dc/ rf magnetron sputtering [17–19], e-beam evaporation [20], spray pyrolysis [21], thermal decomposition [22], neutron irradiation [23], SILAR [24], pulsed laser deposition [25], hydrothermal [26]. Valanarasu et al. [27], investigated on MgO thin flm by spin-coating technique. The transmittance increases as the function of annealing times and it shows sur- face plasmon resonance. The optical band gap lies between 3.81 and 3.92 eV. And it is a potential candidate for semi- conducting device applications. Lee et al. [28], expressed secondary electron emission (SEE) of undoped and tran- sition metal-doped MgO. Doping transition metal to MgO induces local stress due to the expansion and contraction of bond length to adjacent atoms. The bond length of Fe–O is similar to Mg–O. Higher the defect, higher is SEE which * S. Visweswaran visudharan@gmail.com 1 Department of Physics, Annamalai University, Annamalainagar, Chidambaram 608 002, India 2 Department of Physics, Karunya Institute of Technology and Sciences, Coimbatore 641 114, India 3 Department of Physics, Thiru Kolanjiappar Government Arts College, Vridhachalam 606001, India