Direct conversion of β-Ga2O3 thin films to β-Ga2O3 nanowires by annealing in a hydrogen atmosphere

Catalyst-Assisted Large-Area Growth of Single-Crystal β-Ga2O3 Nanowires on Sapphire Substrates by Metal–Organic Chemical Vapor Deposition

“…Before the root of β-Ga 2 O 3 nanowires was grown, due to the surface tension effect, predeposited Au thin film self-assembled into nano islands that were randomly distributed all over the sapphire substrate as the reactor chamber temperature got higher, which could be used as catalysts in the growth of β-Ga 2 O 3 nanowires on sapphire, with Au remaining in liquid form at this stage. [14,26] This could be apparently confirmed by the SEM images showing the growth process of β-Ga 2 O 3 nanowires after 5 min and 30 min, as shown in Figure 2. The inset of Figure 2a clearly illustrates a β-Ga 2 O 3 nanorod underneath an Au nanocrystal after 5 min growth.…”

“…This feature suggests β-Ga 2 O 3 -based nanoscale devices can function stably when used in extreme environments [8]. To address this, a variety of techniques have been employed previously to synthesize β-Ga 2 O 3 nanowires, including physical evaporation [9][10][11][12], arc-discharge [13], vapor-liquid-solid method (VLS) [14][15][16], microwave plasma [17], chemical vapor deposition (CVD) [18][19][20], metalorganic Nanomaterials 2020, 10, 1031 2 of 9 chemical vapor deposition (MOCVD) [21][22][23], and thermal reduction method [24,25], which in all exhibit various limitations in the terms of either growth speed, large-area epitaxy or material quality. More importantly, in practice, processing of nanowire devices usually calls for precisely controlled growth of a highly-oriented nanowire array with a good uniformity in the size of individual nanowires.…”

Liquid Gallium-Assisted Patterned Growth of β-Ga2O3 Nanowires on Metallic Foils for Photocatalytic Dye Degradation

“…Subsequently, the Ag and Ga atoms in the Ag 3 Ga phase could diffuse into the Au NPs to form the tip drops, which acted as a catalyst to induce the growth of nanowires followed by the VLS mechanism. Afterward, the limited tip growth at 550 °C induced a chunk-like shape with a zigzag structure . When the condition for thermal energy was satisfied at 650 °C, the tip drops would continuously absorb the Ga 2 O vapor phase to maintain supersaturation of Ga for nanowire growth .…”

“…Afterward, the limited tip growth at 550 °C induced a chunk-like shape with a zigzag structure. 44 When the condition for thermal energy was satisfied at 650 °C, the tip drops would continuously absorb the Ga 2 O vapor phase to maintain supersaturation of Ga for nanowire growth. 45 Moreover, since the Gibbs free energy (ΔG f ) of Ga (−998.3 kJ mol −1 to Ga 2 O 3 ) was much lower than that of Ag (−11.2 kJ mol −1 to Ag 2 O), 31 gallium oxide dominated the surface of the Ag 3 Ga intermetallic phase after the first thermal treatment, evidenced by XPS (Figure S29).…”