Raman spectroscopy and characterisation of α‐gallium oxyhydroxide and β‐gallium oxide nanorods

Abstract Raman spectroscopy complemented by infrared spectroscopy was used to characterise both gallium oxyhydroxide (α‐GaO(OH)) and gallium oxide (β‐Ga 2 O 3 ) nanorods synthesised with and without the surfactants using a soft chemical methodology at low temperatures. Nano‐ to micro‐sized gallium oxyhydroxide and gallium oxide materials were characterised and analysed by both X‐ray diffraction and Raman spectroscopy. Rod‐like GaO(OH) crystals with average length of ∼2.5 µm and width of 1.5 µm were obtained. Upon thermally treating gallium oxyhydroxide GaO(OH) to 900 °C, β‐Ga 2 O 3 was synthesised retaining the initial GaO(OH) morphology. Raman spectroscopy has been used to study the structure of nanorods of GaO(OH) and Ga 2 O 3 crystals. Raman spectroscopy shows bands characteristic of GaO(OH) at 950 and ∼1000 cm −1 attributed to GaOH deformation modes. Bands at 261, 275, 433 and 522 cm −1 are assigned to vibrational modes involving GaOH units. Bands observed at 320, 346, 418 and 472 cm −1 are assigned to the deformation modes of Ga 2 O 6 octahedra. Two sharp infrared bands at 2948 and 2916 cm −1 are attributed to the GaO(OH) symmetric stretching vibrations. Raman spectroscopy of Ga 2 O 3 provides bands at 630, 656 and 767 cm −1 which are assigned to the bending and stretching of GaO 4 units. Raman bands at 417 and 475 cm −1 are attributed to the symmetric stretching modes of GaO 2 units. The Raman bands at 319 and 347 cm −1 are assigned to the bending modes of GaO 2 units. Copyright © 2008 John Wiley & Sons, Ltd.