Characteristics of aluminium nitride thin film prepared by pulse laser deposition with varying laser pulses

In this work, the studies of Aluminium Nitride (AlN) thin film deposited on silicon (Si) (111) substrate using the pulsed laser deposition (PLD) method, specifically under different number of laser pulses, were performed. From the electron micrographs, the samples exhibited a densely packed granular morphology. The film thickness, particle size, and surface roughness were found to be increasing along with number of laser pulses. X-ray diffraction analysis revealed all AlN samples to have hexagonal wurtzite structure. Additionally, the calculated lattice constants suggest AlN experiences inward biaxial stress during growth. This was in agreement with the Raman results, aside from substantiating the presence of AlN with (100) and (101) plane to be grown. Room temperature photoluminescence (PL) measurements showed band-edge emission was attributed to AlN along with some defect-related bands. Additionally, the band-edge emission shifted to higher photon energy, i.e. 5.49-5.89 eV with increasing laser pulses. Such observations were consistent with that obtained from UV-Vis spectroscopy.