【Substrate Papers】Iron-doped β-Ga₂O₃ single crystal: iron occupying site and optical properties

      Researchers from the Shanghai University have published a dissertation titled "Iron-doped β-Ga₂O₃ single crystal: iron occupying site and optical properties" in CrystEngComm.

Abstract

      β-phase gallium oxide (β-Ga₂O₃) is an extra wide-bandgap semiconductor that has garnered significant attention for its immense potentials in high-power electronic and optoelectronic applications. However, the high electron concentration due to the intrinsic defects restricts the applications of β-Ga₂O₃. Doping with Fe³⁺ can introduce deep acceptors that compensate background n-type conductivity, resulting in semi-insulating characteristics. Therefore, in this report, low-dose Fe³⁺ were doped in β-Ga₂O₃ single crystal (SC) through the edge-defined film-fed growth method. Although X-ray diffraction spectrum of Fe-doped sample showed no distinct difference from that of UID sample, the UV-vis absorption and Fourier Transform infrared spectra indicated the successful incorporation of Fe in the lattice of β-Ga₂O₃ SC. Considering the calculated formation energies of Fe_GaI and Fe_GaII impurities together with the results of Angular-resolved polarization Raman spectra, it was revealed that trace Fe³⁺ ions mainly occupied the Ga_II site and greatly affected the symmetry of the Ga_IO₄ tetrahedra. The temperature-dependent photoluminescence spectra indicated that deep-level defects by introducing trace Fe ions greatly reduce the radiative recombination from donor-acceptor pairs. The identification of occupying site helps to understand the impact of trace Fe on the crystal structure and optical properties, which provides insights for high-resistance β-Ga₂O₃.

DOI：

https://doi.org/10.1039/D5CE00062A