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

Che-Yuan Yeh,Hui Li,Fei-Peng Yu,Dong-Sing Wuu,Yi-Man Zhao,Sam Zhang

doi:10.3390/cryst9110564

Che-Yuan Yeh, Hui Li + Show 4 more

Open Access

https://doi.org/10.3390/cryst9110564

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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%.

Highlights

Environmental protection, especially against water pollution, has generated public interest in recent years, and the application of nanotechnology in this field has become a hot topic
The FE-SEM images of the GaOOH nanostructures obtained via CBD at various Ga(NO3 )3 concentrations are shown in Figure 1, where the length, width, and the aspect ratio of at least eight GaOOH nanorods were measured
The FE-SEM images of the GaOOH nanostructures obtained via CBD at various Ga(NO3)3 concentrations

Summary

Introduction

Environmental protection, especially against water pollution, has generated public interest in recent years, and the application of nanotechnology in this field has become a hot topic. The discharge of untreated MB into the wastewater can lead to serious pollution problems, making degradation and decolorization of MB is one of the important targets of dyeing wastewater treatment [5,6]. Metal oxides, such as titanium dioxide, zinc oxide, and gallium oxide (Ga2 O3 ), are considered promising for photocatalytic applications due to their excellent physical and chemical properties [7,8,9,10,11]. The chemistry of the synthesis process can be summarized as follows [20,28,29,30]:

Experimental

Results and Discussion

O3 obtained

Conclusions