Luminescence and thermally stimulated conductivity of polycrystalline β-Ga2O3: Mn and β-Ga2O3: Mn, Si

Unintentionally doped (UID), Mn, and Mn-Si doped β-Ga2O3 polycrystalline samples were synthesized by high-temperature solid-state chemical reaction. UID β-Ga2O3 has intense host emission in the 350–550 nm wavelength range. The intensity of the luminescence bands in the UV, blue, and green spectral regions decreased strongly by approximately 1000 times in Mn-doped β-Ga2O3 samples. Against a decrease of host emission in doped samples, a weak luminescence band in the yellow–orange range with a maximum of about 605 nm was registered. It was found that doping with manganese increases the resistivity and activation energy of dark conductivity. The activation energy of dark conductivity in UID samples was at about 1 eV and increased to 1.4 eV after doping with manganese ions. Thermally stimulated conductivity (TSC) peaks (E1–E3) are observed in the 300–450 K range for UID gallium oxide samples. Doping with manganese significantly changes the shape of the TSС curves, decreasing the intensity of the TSC peaks at 325 and 350 K and completely disappearing the peak at 385 K. Doping with Mn impurity produces high-resistance gallium oxide, promising for various applications in energy and optoelectronics.