【Other Papers】Hydrothermal process Zn: β-Ga₂O₃ composite or Zn doped β-Ga₂O₃? Unravelling the microstructural and defect evolution

      Researchers from Indian Institute of Technology have published a dissertation titled " Hydrothermal process Zn: β-Ga₂O₃ composite or Zn doped β-Ga₂O₃? Unravelling the microstructural and defect evolution " in Journal of Alloys and Compounds.

Abstract

      Hydrothermally grown and high temperature annealed, pristine and Zn incorporated β-Ga₂O₃ has been investigated to annotate the influence of Zn on the structural, morphological and defect evolution to identify the transition from Zn: β-Ga₂O₃ system to β-Ga₂O₃/ZnGa₂O₄ composite. Formation of polycrystalline, monoclinic structure β-Ga₂O₃ microrods with (C2/m) space group and (111) preferred orientation was confirmed with X-ray Diffraction. With Zn incorporation, change in preferred orientation towards the (-202) plane has been observed, acompanied by formation of cubic spinel ZnGa₂O₄, with Fd-3m space group and (311) plane orientation. upon addition of 15% Zn, secondary phase dominates. FESEM image confirms the formation of microrods for pristine and shows a significant morphological evolution for different Zn-concentration incorporated β-Ga₂O₃. The EDX analysis confirm the elemental composition of Ga, O and Zn present in the samples. Raman spectra supports the coexistance of β-Ga₂O₃ and ZnGa₂O₄ phase with the emergence of additional peaks associated with cubic spinel phase for the Zn incorporated samples. Diffuse reflectance spectra of the samples reveals that with varying Zn concentration, the reflectance decreases while the bandgap varies nonmonotonically. Photoluminescence spectra shows enhanced defect generated emission peaks for ZGO5 and ZGO10 while ZGO15 exhibit broad blue and red emission associated with ZnGa₂O₄ phase. XPS analysis provides the quantitative insight of surface chemical composition and reveals the systematic change in chemical environment in the system. Collectively the results shows that Zn incorporation at lower concentrations, promots the Zn doped system. While, incorporating it at higher concentration, exceed the solubility limit which induce the secondary phase formation, resulting into the formation of β-Ga₂O₃/ ZnGa₂O₄ composite.

DOI：

https://doi.org/10.1016/j.jallcom.2026.190727