GaOOH, and β- And γ-Ga₂O₃ nanowires: Preparation and photoluminescence

A composite methodology using laser ablation followed by a solution refluxing process was demonstrated to prepare GaOOH and (β-, γ-) Ga₂O₃ nanowires, where GaOOH and γ-Ga ₂O₃ nanowires were prepared for the first time. The CTAB surfactant and PVP polymer facilitated the nucleation and growth of GaOOH nanorods, and played different roles in selectively controlling the growth rates of different facets. In the PVA/CTAB-assisted reaction, a high aspect ratio (of at least 200) of GaOOH nanowires was approached. The calcination of GaOOH nanowires at a temperature of 500 °C (6 h) transformed them into γ-Ga₂O₃ nanowires and converted them further into β-Ga₂O₃ nanowires at 750 °C (18 h). Photoluminescence measurements were conducted at room temperature for the GaOOH and (β-, γ-) Ga₂O₃ nanowires using a high resolution synchrotron X-ray source. The blue emissions from the GaOOH and (β-, γ-) Ga₂O₃ nanowires were resolved into a few sharp peaks, and may provide a valuable reference for further understanding the PL mechanisms. Although luminescence spectra of the GaOOH and γ-Ga₂O₃ nanowires were recorded for the first time, the similar optical band gap and emission contour observed for β-Ga ₂O₃ nanowires suggests that the optical behavior of GaOOH and γ-Ga₂O₃ nanowires are likely to closely follow the PL mechanisms of β-Ga₂O₃ nanowires.