Crystallization Effects of Nanocrystalline GaN Films on Field Emission

Abstract

Nanocrystalline GaN films are fabricated on Si substrates by pulsed laser deposition to achieve enhanced field emission (FE) based on microstructural engineering. In the process, the microstructure including crystallization and orientation can be conveniently and directly modulated by the temperature. XRD reveals that the fabrication temperature affects the crystallinity and grain size of the GaN films. A strong correlation between the microstructure and FE properties is also observed. The turn-on electric field decreases from 30.5 to 2.3 V/μm, and the FE current density increases by two to three orders of magnitude based on the microstructure of the GaN films. A qualitative grain boundary conduction model is proposed to explain the strong correlation between the microstructure and FE properties. The results demonstrate the importance of microstructural effects on FE, and they must be considered in the design and production of FE GaN devices.

Structural effects of field emission from GaN nanofilms on SiC substrates

“…20 Simultaneously, the appearance of only the (0002) diffraction peak of GaN related to Ga indicates that the GaN NFs are preferentially oriented in the c-axis direction. 18 The XRD results confirm that the films deposited are GaN NFs.…”

“…18. Here, the target used for deposition of GaN NFs was prepared from GaN powders by pressing and sintering at 560 C in a sintering furnace.…”

“…The optical properties of GaN films grown on SiC substrates have been studied extensively, [15][16][17] but their FE properties have seldom been investigated. Previously, we studied the FE properties of GaN NFs grown on silicon substrates; 18 here, we investigate the FE properties of GaN NFs grown on SiC substrates. We examine the dependence of FE from GaN NFs on SiC substrates on preparation conditions.…”

Growth and Excellent Field Emission Properties of GaN Nanopencils and Nanotowers

“…The F-N curves inset in Fig.4a and Fig.4b are linear approximately, which indicate that the field electron emissions of the samples are caused by vacuum tunneling effect [16] . [5,[8][9][10][11][12][13][15][16][17][18][19][20][21][22][23]. We believe this result is due to (1) The morphology of GaN is like a hedgehog, and the sharp ends of GaN nanopencils benefit to electron emission; (2) The surface of the GaN nanotowers is a layer structure, so there are numerous edges on the surface of the GaN nanotowers.…”

Analysis of Wetting Characteristics on Microstructured Hydrophobic Surfaces for the Passive Containment Cooling System

“…Si is one of the particularly promising coating materials because of low cost [11], higher thermal conductivity [12], favorable chemical stability [13], and mature processing technologies. Therefore, as the coating material, Si has great advantages in the heat transfer requirements of CV.…”