The growth of ultralong and highly blue luminescent gallium oxide nanowires and nanobelts, and direct horizontal nanowire growth on substrates

Abstract

We report the growth of ultralong β-Ga(2)O(3) nanowires and nanobelts on silicon substrates using a vapor phase transport method. The growth was carried out in a tube furnace, with gallium metal serving as the gallium source. The nanowires and nanobelts can grow to lengths of hundreds of nanometers and even millimeters. Their full lengths have been captured by both scanning electron microscope (SEM) and optical images. X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images have been used to study the crystal structures of these nanowires and nanobelts. Strong blue emission from these ultralong nanostructures can be readily observed by irradiation with an ultraviolet (UV) lamp. Diffuse reflectance spectroscopy measurements gave a band gap of 4.56 eV for these nanostructures. The blue emission shows a band maximum at 470 nm. Interestingly, by annealing the silicon substrates in an oxygen atmosphere to form a thick SiO(2) film, and growing Ga(2)O(3) nanowires over the sputtered gold patterned regions, horizontal Ga(2)O(3) nanowire growth in the non-gold-coated regions can be observed. These horizontal nanowires can grow to as long as over 10 µm in length. Their composition has been confirmed by TEM characterization. This represents one of the first examples of direct horizontal growth of oxide nanowires on substrates.

Hydride-assisted growth of GaN nanowires on Au/Si(001) via the reaction of Ga with NH3 and H2

“…The Ga 2 O 3 NWs have diameters r50 nm, lengths up to 10 mm and exhibited peaks in the XRD corresponding to b-Ga 2 O 3 as shown in Fig. 3(b) [33]. No nanostructures were obtained for T G o800 1C due to the fact that Ga has a low melting point of 29.8 1C together with an unusually high boiling point of 1983 1C and high surface tension, hence a low vapor pressure even at temperatures of a few hundreds 1C.…”

A One‐Step Method for the Growth of Ga2O3‐Nanorod‐Based White‐Light‐Emitting Phosphors

“…As evident from the SEM and TEM images, the Ga 2 O 3 nanorods do not have any catalyst at the tip, indicating that the growth is not through a VLS mechansim. [30,31] We suggest a mechanism in which nanorods are obtained by the nucleation, coalescence, evaporation, and condensation of Ga 2 O 3 particles that are formed initially in the growth process. After heating the molten Gallium in a quartz boat at 1300 8C for 1 h, sub-micrometer-sized irregularly shaped particles and short nanorods are formed (Fig.…”

Metal Oxide Nanostructures: Growth and Applications

“…In another study, Kuo and Huang [58] have reported the growth of ultra-long Ga 2 O 3 nanowires and nanobelts using CVD technique. The length of nanostructures was in sub-millimeter or millimeter range.…”

“…The constant supply for Ga vapours for extended hours and residual oxygen present in the growth chamber played a crucial role in the growth of extra-long Ga 2 O 3 nanostructures. Two silicon [57,58] substrates coated with gold catalyst were placed in the growth chamber at two different places. One substrate (position-1) was directly placed on the Ga source and second a substrate (position-2, 3-5 mm from the Ga source) was placed downstream direction near to the Ga source.…”