Dynamics Contributions to the Growth Mechanism of Ga2O3 Thin Film and NWs Enabled by Ag Catalyst

Improvement of Schottky Contacts of Gallium Oxide (Ga2O3) Nanowires for UV Applications

Interest in the synthesis and fabrication of gallium oxide (Ga₂O₃) nanostructures as wide bandgap semiconductor-based ultraviolet (UV) photodetectors has recently increased due to their importance in cases of deep-UV photodetectors operating in high power/temperature conditions. Due to their unique properties, i.e., higher surface-to-volume ratio and quantum effects, these nanostructures can significantly enhance the sensitivity of detection. In this work, two Ga₂O₃ nanostructured films with different nanowire densities and sizes obtained by thermal oxidation of Ga on quartz, in the presence and absence of Ag catalyst, were investigated. The electrical properties influenced by the density of Ga₂O₃ nanowires (NWs) were analyzed to define the configuration of UV detection. The electrical measurements were performed on two different electric contacts and were located at distances of 1 and 3 mm. Factors affecting the detection performance of Ga₂O₃ NWs film, such as the distance between metal contacts (1 and 3 mm apart), voltages (5–20 V) and transient photocurrents were discussed in relation to the composition and nanostructure of the Ga₂O₃ NWs film.

Gallium oxide nanowires for UV detection with enhanced growth and material properties

In the last decade, interest in the use of beta gallium oxide (β-Ga₂O₃) as a semiconductor for high power/high temperature devices and deep-UV sensors has grown. Ga₂O₃ has an enormous band gap of 4.8 eV, which makes it well suited for these applications. Compared to thin films, nanowires exhibit a higher surface-to-volume ratio, increasing their sensitivity for detection of chemical substances and light. In this work, we explore a simple and inexpensive method of growing high-density gallium oxide nanowires at high temperatures. Gallium oxide nanowire growth can be achieved by heating and oxidizing pure gallium at high temperatures (~ 1000 °C) in the presence of trace amounts of oxygen. This process can be optimized to large-scale production to grow high-quality, dense and long Ga₂O₃ nanowires. We show the results of morphological, structural, electrical and optical characterization of the β-Ga₂O₃ nanowires including the optical bandgap and photoconductance. The influence of density on these Ga₂O₃ nanowires and their properties will be examined in order to determine the optimum configuration for the detection of UV light.

Influence of Silver as a Catalyst on the Growth of β-Ga2O3 Nanowires on GaAs

A simple and inexpensive thermal oxidation process was performed to synthesize gallium oxide (Ga₂O₃) nanowires using Ag thin film as a catalyst at 800 °C and 1000 °C to understand the effect of the silver catalyst on the nanowire growth. The effect of doping and orientation of the substrates on the growth of Ga₂O₃ nanowires on single-crystal gallium arsenide (GaAs) wafers in atmosphere were investigated. A comprehensive study of the oxide film and nanowire growth was performed using various characterization techniques including XRD, SEM, EDS, focused ion beam (FIB), XPS and STEM. Based on the characterization results, we believe that Ag thin film produces Ag nanoparticles at high temperatures and enhances the reaction between oxygen and gallium, contributing to denser and longer Ga₂O₃ nanowires compared to those grown without silver catalyst. This process can be optimized for large-scale production of high-quality, dense, and long nanowires.

Comparative Study of Growth Morphologies of Ga2O3 Nanowires on Different Substrates

Gallium oxide (Ga₂O₃) is a new wide bandgap semiconductor with remarkable properties that offers strong potential for applications in power electronics, optoelectronics, and devices for extreme conditions. In this work, we explore the morphology of Ga₂O₃ nanostructures on different substrates and temperatures. We used silver catalysts to enhance the growth of Ga₂O₃ nanowires on substrates such as p-Si substrate doped with boron, 250 nm SiO₂ on n-Si, 250 nm Si₃N₄ on p-Si, quartz, and n-Si substrates by using a thermal oxidation technique at high temperatures (~1000 °C) in the presence of liquid silver paste that served as a catalyst layer. We present the results of the morphological, structural, and elemental characterization of the Ga₂O₃ nanostructures. This work offers in-depth explanation of the dense, thin, and long Ga₂O₃ nanowire growth directly on the surfaces of various types of substrates using silver catalysts.

The Growth of Ga2O3 Nanowires on Silicon for Ultraviolet Photodetector

We investigated the effect of silver catalysts to enhance the growth of Ga₂O₃ nanowires. The growth of Ga₂O₃ nanowires on a P⁺-Si (100) substrate was demonstrated by using a thermal oxidation technique at high temperatures (~1000 °C) in the presence of a thin silver film that serves as a catalyst layer. We present the results of morphological, compositional, and electrical characterization of the Ga₂O₃ nanowires, including the measurements on photoconductance and transient time. Our results show that highly oriented, dense and long Ga₂O₃ nanowires can be grown directly on the surface of silicon. The Ga₂O₃ nanowires, with their inherent n-type characteristics formed a pn heterojunction when grown on silicon. The heterojunction showed rectifying characteristics and excellent UV photoresponse.