Raman spectroscopy of the transition of α‐gallium oxyhydroxide to β‐gallium oxide nanorods

The thermo‐Raman spectra of synthesised α‐gallium oxyhydroxide nanorod prove that the transition of α‐gallium oxyhydroxide to β‐gallium oxide nanorods occurs above 350 °C but below 400 °C. Scanning electron microscopy proves that the morphology of the α‐gallium oxyhydroxide nanorods is retained upon calcination to β‐gallium oxide. X‐ray diffraction patterns show that the nanorods are α‐gallium oxyhydroxide converting upon calcination to β‐gallium oxide. Intense Raman bands are observed at 190, 262, 275, 430, 520, 605, and 695 cm⁻¹, which undergo a red shift of ∼5 cm⁻¹ upon heating to 350 °C. Upon thermal treatment above 350 °C, the Raman spectrum shows a significantly different pattern. Raman bands are observed at 155, 212, 280, 430, 570, and 685 cm⁻¹. The thermo‐Raman spectra are in harmony with the TG and DTG patterns, which show that the reaction of α‐gallium oxyhydroxide to β‐gallium oxide occurs at 365 °C. Copyright © 2008 John Wiley & Sons, Ltd.