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

GaN films with orientation along c -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 ) 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 β (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 ) 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.