CL study of blue and UV emissions in β-Ga2O3 nanowires grown by thermal evaporation of GaN

Abstract

We report a cathodoluminescence (CL) study of β-Ga2O3 nanowires grown by thermal evaporation of GaN on Si(100) and Au/Si(00) substrates. Condensation and subsequent oxidation of metallic Ga is suggested as the growth mechanism of β-Ga2O3 nanowires. The β-Ga2O3 nanowires grown on Si(100) show multiple bends or undulations, together with a strong UV emission at 3.31 eV and a weak blue emission centered at 2.8 eV as a band component. The β-Ga2O3 nanowires grown on Au/Si(100) substrates recorded a lower CL intensity of a well-defined blue emission of 2.8 eV. A thermal treatment on these samples produced an increase of the UV emission and quenching of the blue band. Thermal annealing of oxygen vacancies is proposed as the responsible mechanism for the observed behavior of these samples.

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

“…It emits blue, UV, green and red emission bands. The origin of all these emission bands (1.7–4.0 eV) has been suggested by several authors 16–35. UV emission (3.45 eV) was independent of dopant and growth conditions.…”

“…The CL investigation on undoped and doped bulk Ga 2 O 3 has been carried out by several groups 24, 27, 28, 86, 87. The CL emission mechanism is similar to the PL emission mechanism, which we have discussed in a previous section.…”

“…One very important advantage of β‐Ga 2 O 3 NWs is their large surface to volume ratio providing more surface states to interact with the surroundings. Due to the wide bandgap, a large number of defect states are available inside the β‐Ga 2 O 3 NS; hence it emits a wide range of defect emissions from the infrared to the UV due to these defect states 16–35. The luminescence properties of undoped and doped β‐Ga 2 O 3 have been studied in the form of bulk 16–21 and NS 21–35 earlier.…”

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].…”

Photocatalytic degradation of organic pollutants by shape selective synthesis of β-Ga2O3 microspheres constituted by nanospheres for environmental remediation

“…2,3 Both physical and chemical properties of nanostructures are associated with their size, shape and dimensionality; therefore morphology controlled synthesis of functional nanostructures gain importance in scientific and technological perspectives. 5,6 In order to grow β-Ga 2 O 3 nanostructures, wet chemical approaches such as reflux condensation method, sol-gel, hydrothermal process and precipitation technique have been employed. There is an increasing interest in pursuing effective synthesis strategies for the fabrication of advanced materials with complex shape and hierarchical organization.…”