Physical and optical characteristics of α-Al₂O₃ nano coating formed by pulsed laser deposition technique

Due to the importance of Al₂O₃ nano-coatings in different fields, further studies and investigations are required. In addition, few studies about preparing Al₂O₃ by pulsed laser deposition have been found; hence this method was selected for Al₂O₃ preparation. Alumina (α-Al₂O₃) is deposited to form nano-coating film using pulsed laser deposition (PLD) on Indium Tin Oxide (ITO) substrate. Laser pulses are applied in three sets of 100, 200, and 300. The combination of the number of laser pulses and energies of 700, 800, and 900 mJ are made to study the crystal structure, surface morphology, and optical properties of the nanocoated. The crystal structure analyses using XRD showed that nano-coating has a polycrystalline structure. The AFM analyses showed that the average surface roughness proportion with the energy and the number of pulses increased from 0.6 nm to 2.9 nm. The transmission decreased with increasing laser energy and the number of pulses. The optical bandgap from 4.11 to 4.01ev is also obtained. For the first time, this study demonstrates three energies and three sets of pulses associated with a fixed substrate temperature of 200ºC; optical characteristics were studied extensively under PLD technique conditions.