Growth and Characterization of Ga2O3 for Power Nanodevices Using Metal Nanoparticle Catalysts

Abstract

A simple and inexpensive thermal oxidation process is used to grow β-Ga₂O₃ oxide (β-Ga₂O₃) thin films/nanorods on a c-plane (0001) sapphire substrate using Ag/Au catalysts. The effect of these catalysts on the growth mechanism of Ga₂O₃ was studied by different characterization techniques, including X-ray diffraction analysis (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray analysis (EDX). The XRD results of the grown Ga₂O₃ on a sapphire substrate show three sharp diffraction peaks located at 19.31°, 38.70° and 59.38° corresponding to the 2¯01, 4¯02 and 6¯03 planes of β-Ga₂O₃. Field Emission Scanning Electron Microscope (FESEM) analysis showed the formation of longer and denser Ga₂O₃ nanowires at higher temperatures, especially in the presence of silver nanoparticles as catalysts.

Keywords: catalysts; gold; silver; thermal oxidation; β-Ga2O3.

Figure 1

Graphical illustration of sample set-up inside the furnace used for growing and studying the morphology of Ga₂O₃ using different catalysts.

Figure 2

XRD pattern of β-Ga₂O₃ nanowires grown on the surface of sapphire at 800 °C: (a) Ag NP catalyst, (b) Au NP catalyst.

Figure 3

FWHM of $\left(\overline{2}01\right)$ diffraction peak of β-Ga₂O₃ with different catalyst loading at 800 °C: (a) Ag catalyst, (b) Au catalyst.

Figure 4

Effect of the oxidation temperature on the growth of Ga₂O₃ in the presence of Au NPs (a) at 800 °C; (b) at 900 °C and in the presence of Ag NPs (c) at 800 °C; (d) at 900 °C.

Figure 5

FESEM Images of Ga₂O₃ nanostructures grown using Au. (a,b) Low Ga concentration at 800 °C and 900 °C. (c,d) High Ga concentration at 800 °C and 900 °C.

Figure 6

FESEM Images of Ga₂O₃ nanostructure grown using Ag. (a,b) Low Ga concentration at 800 °C and 900 °C. (c,d) High Ga concentration at 800 °C and 900 °C.

Figure 7

FESEM image of Ga₂O₃ nucleation grown using Ga is ~1.03 g and (a) 10 mg Au NPs and (b) Ag NPs at 800 °C.

Figure 8

FESEM images of Ga₂O₃ nanostructures grown in the presence of 10 mg of Ag NPs at 800 °C. (a) 0.5 g of Ga; (b) 1.0 g of Ga; (c) 1.5 g of Ga.

Figure 9

A schematic that summarizes the growth mechanism to obtain denser and longer Ga₂O₃ nanostructures in the presence of metal nanoparticles catalyst such as Au NPs or Ag NPs.

Figure 10

FESEM images of Ga₂O₃ nanostructures grown at 800 °C with 1.5 g of Ga and 5 mg of catalyst. (a) Au NPs. (b) Ag NPs.

Figure 11

FESEM images of Ga₂O₃ nanostructures grown at 900 °C with 1.5 g of Ga and different catalyst concentrations. (a) 5 mg of Au, (b) 10 mg of Au, (c) 15 mg of Au, (d) 5 mg of Ag, (e) 10 mg of Ag and (f) 15 mg of Ag.

Figure 12

FESEM-EDS images of Ga₂O₃ nanostructure grown using Au NPs and Ag NPs. The left column at 800 °C and the right column at 900 °C; (a,f) are without catalyst; (b,g) shows Ga₂O₃ nanostructure grown using Ga is ~1.03 g and 10 mg Au NPs; (c,h) shows Ga₂O₃ nanostructure grown using Ga is ~1.5 g and 10 mg Au NPs; (d,i) show Ga₂O₃ nanostructure grown using Ga is ~1.03 g and 10 mg Ag NPs; (e,j) show Ga₂O₃ nanostructure grown using Ga is ~1.5 g and 10 mg Ag NPs.