Undoped and Mg²⁺-doped β-Ga₂O₃-20% In₂O₃ solid solution microcrystalline samples were synthesized using the high-temperature solid-state chemical reaction method to investigate the influence of native defects on structural, luminescent, and electrical properties. The synthesis process involved varying the oxygen partial pressure by synthesizing samples in either an oxygen or argon atmosphere. X-ray diffraction (XRD) analysis confirmed the monoclinic structure of the samples with the lattice parameters and unit cell volume fitting well to the general trends of the (Ga_1−xIn_x)₂O₃ solid solution series. Broad emission spectra ranging from 1.5 to 3.5 eV were registered for all samples. Luminescence spectra showed violet, blue, and green emission elementary bands. The luminescence intensity was found to vary depending on the synthesis atmosphere. An argon synthesis atmosphere leads to increasing violet luminescence and decreasing green luminescence. Intense bands at about 4.5 and 5.0 eV and a low-intensity band at 3.3 eV are presented in the excitation spectra. The electrical conductivity of the samples was also determined depending on the synthesis atmosphere. The high-resistance samples obtained in an oxygen atmosphere exhibited activation energy of around 0.98 eV. Samples synthesized in an argon atmosphere demonstrated several orders of magnitude higher conductivity with an activation energy of 0.15 eV. The results suggest that the synthesis atmosphere is crucial in determining the luminescent and electrical properties of undoped β-Ga₂O₃-In₂O₃ solid solution samples, offering the potential for various optoelectronic applications.

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.

The effect of a weak magnetic field (B = 0.17 T) and X-irradiation (D < 520 Gy) on the rearrangement of the defective structure of near-surface p-type silicon layers was studied. It was established that the effect of these external fields increases the positive accumulated charge in the region of spatial charge (RSC) and in the SiO₂ dielectric layer. This can be caused by both defects in the near-surface layer of the semiconductor and impurities contained in the dielectric layer, which can generate charge carriers. It was found that the near-surface layers of the barrier structures contain only one deep level in the silicon band gap, with an activation energy of Ev + 0.38 eV. This energy level corresponds to a complex of silicon interstitial atoms Si_I+Si_I. When X-irradiated with a dose of 520 Gy, a new level with the energy of Ev + 0.45 eV was observed. This level corresponds to a point boron radiation defect in the interstitial site (B_I). These two types of defect are effective in obtaining charge carriers, and cause deterioration of the rectifier properties of the silicon barrier structures. It was established that the silicon surface is quite active, and adsorbs organic atoms and molecules from the atmosphere, forming bonds. It was shown that the effect of a magnetic field causes the decay of adsorbed complexes at the Si–SiO₂ interface. The released hydrogen is captured by acceptor levels and, as a result, the concentration of more complex Si–H₃ complexes increases that of O₃–Si–H.

Photoluminescence, luminescence excitation spectra, and electrical conductivity of β-Ga2O3-In2O3 solid solutions were studied. For this purpose, polycrystalline samples of unintentionally doped (UID) and doped with Ca or Zr β-Ga2O3-In2O3 solid solution with 20% In were synthesized and characterized. All samples were obtained by the high-temperature solid-phase method from appropriate oxides at 1300 °C at low and high oxygen partial pressure. It was established that UID and doped with Ca2+ or Zr4+ samples synthesized in an oxygen atmosphere were highly resistive, while the samples synthesized in an argon atmosphere had high conductivity. The conductivity was the lowest in the samples doped with Ca2+ and was 10−13 Ω−1 cm−1, while in the samples doped with Zr4+, the electrical conductivity was the highest and reached 10−3 Ω−1 cm−1. The broadband luminescence of β-Ga2O3-In2O3 solid solution is a superposition of three elementary bands with maxima in the violet 3.08 eV, blue 2.73 eV, and green 2.45 eV regions of the spectrum. Doping with Ca2+ or Zr4+ impurities and varying the synthesis atmosphere led mainly to a redistribution of intensities between the elementary luminescence bands. The luminescence arises from the radiative recombination of charge carriers through donor–acceptor pairs and self-localized holes. Donors and acceptors are formed by native defects such as (Gai, VGa, VGaVo) or doping impurities (Zr4+, Ca2+). Unlike the luminescence spectra, the luminescence excitation spectra change significantly when the synthesis conditions vary or when doping with divalent impurities. The excitation band at 4.46 eV is due to electron transitions from the VGa or VGaVO acceptor levels to the conduction band. Electron transitions from acceptor levels of Ca2+ impurities are manifested in the intense excitation band at 4.1 eV.