Fabrication of GaN nanocrystalline thin films Schottky metal-semiconductor-metal ultraviolet photodetectors

Gallium nitride nanocrystalline thin films (GaN NCTH) were prepared on Si substrates using the radio frequency magnetron sputtering (RF) method. XRD patterns with narrow peaks intensity and field emission scanning electron microscopy (FESEM) images exhibits of the GaN nanoparticles have covered surfaces of the substrate with a regular distribution smooth and an average particles size proximately between are 10-20 nm. AFM indicates a smooth surface and RMS is 1.38 nm of GaN NCTH and the optical band gap was calculated to be 3.38 eV. The current-voltage characteristic of metal-semiconductor-metal (M-S-M) GaN ultraviolet photodetectors (UV-PD) in the dark and irradiated with 370 nm light and intensity was (1.4) mW/cm(2) evaluated under bias voltages of -1 to 5 V. The average rise time speed of the photodetector is about 22 ms when current increases from 10 % to 90 % of its value of saturation, while the average fall time is 17 ms when current decreases from 90 % to 10 % of its value of saturation. UV-PD displays 19-261 sensitivity at a different voltage bias; internal photodetector gain between the low value is 1.19 at 8 V and 1.59 at 2 V.