Growth and Photocatalytic Properties of Gallium Oxide Films Using Chemical Bath Deposition

Abstract

Gallium oxide (Ga2O3) thin films were fabricated on glass substrates using a combination of chemical bath deposition and post-annealing process. From the field-emission scanning electron microscopy and x-ray diffraction results, the GaOOH nanorods precursors with better crystallinity can be achieved under higher concentrations (≥0.05 M) of gallium nitrate (Ga(NO3)3). It was found that the GaOOH synthesized from lower Ga(NO3)3 concentration did not transform into α-Ga2O3 among the annealing temperatures used (400–600 °C). Under higher Ga(NO3)3 concentrations (≥0.05 M) with higher annealing temperatures (≥500 °C), the GaOOH can be transformed into the Ga2O3 film successfully. An α-Ga2O3 sample synthesized in a mixed solution of 0.075 M Ga(NO3)3 and 0.5 M hexamethylenetetramine exhibited optimum crystallinity after annealing at 500 °C, where the α-Ga2O3 nanostructure film showed the highest aspect ratio of 5.23. As a result, the photodegeneration efficiencies of the α-Ga2O3 film for the methylene blue aqueous solution can reach 90%.

Polydopamine Shell as a Ga3+ Reservoir for Triggering Gallium–Indium Phase Separation in Eutectic Gallium–Indium Nanoalloys

“…The band around 565 cm –1 in the FTIR spectrum of EGaIn nanoalloys is related to the Ga–O in Ga 2 O 3 (Figure a) . Another two bands at ∼732 and 3400 cm –1 , corresponding to the Ga–O–H stretching vibration and the O–H stretching mode, revealed the formation of GaOOH . However, these two bands cannot be found in the FTIR spectrum of nanoalloy@PDA-0, indicating the absence of GaOOH in nanoalloy@PDA-0, which agrees with the XRD and XPS analysis.…”

“…67 Another two bands at ∼732 and 3400 cm −1 , corresponding to the Ga−O−H stretching vibration and the O−H stretching mode, revealed the formation of GaOOH. 68 However, these two bands cannot be found in the FTIR spectrum of nanoalloy@PDA-0, indicating the absence of GaOOH in nanoalloy@PDA-0, which agrees with the XRD and XPS analysis. When the coating becomes thicker, two strong bands related to PDA at ∼443 and 630 cm −1 are observed, which confirms the successful PDA coating.…”

Chemical Synthesis of β-Ga2O3 Microrods on Silicon and Its Dependence on the Gallium Nitrate Concentration

“…This strategy has been widely used for growing ZnO nanostructures 41,42 and also developed by several groups to obtain GaOOH microrods directly deposited on the substrate. 17,19,43,44 However, Taşet al showed the advantage of using a simple forced hydrolysis to obtain GaOOH microrods by CBD without any chemical additives and at low temperature and ambient pressure, opening the way for developing a green chemistry process.…”

“…A common strategy has consisted of adding urea or hexa­methylene­tetramine (HMTA) in aqueous solution, which progressively releases OH – ions and hence maintains a fairly small constant S R . This strategy has been widely used for growing ZnO nanostructures , and also developed by several groups to obtain GaOOH microrods directly deposited on the substrate. ,,, However, Taş et al showed the advantage of using a simple forced hydrolysis to obtain GaOOH microrods by CBD without any chemical additives and at low temperature and ambient pressure, opening the way for developing a green chemistry process.…”

Extraction of Ga(III) by Di‐(2‐ethylhexyl)phosphoric acid (D2EHPA)‐Modified XAD‐4 Resins Prepared by Solvent‐Nonsolvent Modification

“…Calculation based on MINEQL+ software, depending on the pH value, demonstrates that various trivalent gallium ions such as Ga 3+ , Ga(OH) 2+ , GaO + , GaO 2-, H 2 GaO 3-, Ga(OH) 4-, HGaO 3 2-, GaO 3 3-, and Ga 2 O 3 may exist in aqueous solutions [25,26]. At higher pH, the negatively charged Ga(III) species dominate.…”