Structural effects of field emission from GaN nanofilms on SiC substrates

• Published in: Journal of applied physics 2014-04, Vol.115 (15)
• Main Authors: Chen, Cheng-Cheng, Wang, Ru-Zhi, Liu, Peng, Zhu, Man-Kang, Wang, Bi-Ben, Yan, Hui
• Format: Article
• Language: English
• Subjects: Applied physics; Atomic beam spectroscopy; ATOMIC FORCE MICROSCOPY; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CURRENT DENSITY; Emission analysis; ENERGY BEAM DEPOSITION; FIELD EMISSION; GALLIUM NITRIDES; LASER RADIATION; Microscopy; Nanoparticles; NANOSCIENCE AND NANOTECHNOLOGY; NANOSTRUCTURES; Nanotechnology devices; PARTICLES; PULSED IRRADIATION; Pulsed laser deposition; Pulsed lasers; ROUGHNESS; SCANNING ELECTRON MICROSCOPY; SILICON CARBIDES; Straight lines; STRESSES; SUBSTRATES; X ray spectra; X-RAY DIFFRACTION; X-RAY PHOTOELECTRON SPECTROSCOPY
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4871539

GaN nanofilms (NFs) with different structures are grown on SiC substrates by pulsed laser deposition under different conditions. The synthesized GaN NFs are studied by X-ray diffraction, field-emission (FE) scanning electron microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The GaN NFs are composed of diversified GaN nanoparticles with a diameter of 9–38 nm, thickness of 10–50 nm, and roughness of 0.22–13.03 nm. FE from the GaN NFs is structure dependent, which is explained by stress changing the band gap of the NFs. By structure modulation, the turn-on field of GaN NFs can be as low as 0.66 V/μm at a current density of 1 μA/cm2, with a current density of up to 1.1 mA/cm2 at a field of 4.18 V/μm. Fowler-Nordheim curves of some samples contain multiple straight lines, which originate from the structural change and diversification of GaN nanoparticles under an applied field. Overall, our results suggest that GaN NFs with excellent FE properties can be prepared on SiC substrates, which provides a new route to fabricate high-efficiency FE nanodevices.