Ultrafast VLS growth of epitaxial β- Ga₂O₃nanowires

Abstract

Well-defined monoclinic nanostructures of beta- Ga(2)O(3) were grown in a chemical vapor deposition apparatus using metallic gallium and oxygen as sources. Stable growth conditions were deduced for nanorods, nanoribbons, nanowires and cones. The types of nanostructures are determined by the growth temperature. We suppose that the vapor-solid growth mechanism rules the growth of nanoribbons and rods. For the nanowires we observed catalytic gold droplets atop, characteristic for the VLS growth mechanism with an extremely high growth rate of up to 10 microm min(-1). Nanowires grown on Al(2)O(3) substrates showed an excellent tendency to grow epitaxially, mapping the hexagonal symmetry of Al(2)O(3)(0001).

Nanofunctional gallium oxide (Ga2O3) nanowires/nanostructures and their applications in nanodevices

“…The β‐Ga 2 O 3 NS including NWs, nanosheets, nanobelts, nanorods and nanotubes have been synthesized using several techniques 49–81. Here, in this section, we will first discuss about the growth mechanism involved in the formation of NS, and then give the description of various growth techniques including structural and morphological characterization of β‐Ga 2 O 3 NS.…”

“…On the other hand, the advantages of low‐temperature CVD are that NWs with a large variety of diameters and lengths can be grown epitaxially on substrates. There are many reports where Ga 2 O 3 NS/NWs were fabricated using CVD method 64–77. The schematic diagram of a typical CVD system is shown in Fig.…”

“…In the literature, various synthesis techniques have been employed to grow β‐Ga 2 O 3 NWs/NS 49–80 including thermal evaporation by evaporating a bulk gallium target under controlled conditions, laser‐ablation growth occurs without a catalyst, arc‐discharge by electrical discharge of GaN powders mixed with small amount of transition metals, thermal chemical vapor deposition (CVD) by evaporating pure gallium metal as a Ga vapor source under different conditions in a tubular furnace, carbothermal reduction, metalorganic CVD (MOCVD) using a single‐source organometallic precursor at low temperature, microwave plasma, and so on. Some details of these methods will be discussed in a later section that is devoted to the growth of β‐Ga 2 O 3 NWs/NS.…”

Diameter Tuning of β $$ \beta $$ -Ga2O3 Nanowires Using Chemical Vapor Deposition Technique

“…For nanowire growth, vapor-liquid-solid (VLS) or vapor-solid (VS) process are well established growth mechanisms [22]. The β-Ga 2 O 3 nanostructures including nanowires, nanosheets, nanobelts, and nanorods grown by CVD have been shown in number of reports [12, 20, 23, 24]. Nanowires as building blocks of nanodevices allow tuning of fundamental optical and electronic properties of devices by tuning nanowire diameter.…”

Synthesis and characterization of β-Ga 2 O 3 nanowires on amorphous substrates using radio-frequency powder sputtering

“…Several techniques, such as chemical vapor deposition and thermal evaporation, are employed to synthesize β-Ga 2 O 3 NWs, and the unprecedented properties of the NWs, distinct from those of bulk materials, have been characterized [5][6][7][8]. Typically, a metal catalyst such as Au is used as a seed material to grow NWs by a vapor-liquid-solid (VLS) mechanism [5,9]. It is also wellknown that high-temperature annealing of β-Ga 2 O 3 powders is a very efficient method for fabricating long NWs without catalysts via a vapor-solid mechanism [10,11].…”