Field emission studies of nanostructured cc-axis oriented GaN film on SiOx /Si(100) by pulsed laser deposition

GaN films with orientation along cc-axis were deposited on SiOx/Si(100) substrates using pulsed laser deposition (PLD). Formation of nanostructures of GaN was confirmed using X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. The field electron emission (FE) from the specimen was obtained using a diode configuration and the current–voltage (I–V)(I–V) characteristics were studied. Linear nature of the Fowler–Nordheim (FN) plot indicates that the electron emission is due to the FN tunneling process. High field enhancement factor ββ (28 756) suggests that the field enhancement is due to the nanometric needle-like structures present in the film surface, acting as emitters. The field emission current–time (I–t)(I–t) records were obtained at the preset current density of 0.4 μA/cm2 and 2.0 μA/cm2 for 2.5 h. The fluctuations about the average preset current densities were observed to be 20% and 50% for higher and lower current densities respectively.