The photoluminescence, excitation, and absorption spectra as well as the electrical conductivity of β-Ga2O3:Cr and β-Ga2O3:Cr,Mg single crystals were studied. The as-grown β-Ga2O3:Cr crystals had a green color, the conductivity at about 10−2–10−3 Ω−1 cm−1, and a low yield of Cr3+ impurity luminescence. Annealing in oxygen atmosphere led to a strong increase in Cr3+ red luminescence yield, increase in the resistivity, and changes in the absorption and excitation spectra. Similarly, increases in the Cr3+ luminescence yield and resistivity were observed after codoping of β-Ga2O3:Cr crystals with magnesium (Mg2+). The registered changes in the Cr3+ luminescence yield, electrical conductivity, and in the absorption and excitation spectra are considered to be due to the shift in the Fermi level. In the as-grown β-Ga2O3:Cr crystals, the Fermi level is located near the bottom of the conduction band, and most chromium ions are in the Cr2+ charge state. Annealing in an oxygen atmosphere as well as codoping of the crystals with chromium and magnesium impurities moves the Fermi level toward the middle of the bandgap and recharges the chromium ions to the Cr3+ state.

PACS 61.50. Ks, 61.72.Ff, 68.35.bg The deposition of Al film onto the (111) surface of a p-Si crystal was shown to induce a deformation in the near-surface layer of the latter. Provided that the crystal strain is elastic and uniaxial, the gettering of defects in the near-surface layer is observed, which is confirmed by a change in the dependence of the specimen resistance on the elastic strain magnitude. The maximum depth of the defect capture has been calculated on the basis of the energy of interaction between the deformed layer and dislocations. K e y w o r d s: uniaxial elastic strain, crystal lattice, heterostructure, epitaxial growth, gettering, Cottrell atmosphere.

Представлено дослiдження дефектiв, яким вiдповiдають глибокi енерґетичнi рiвнi в забороненiй зонi кремнiю за допомогою ємнiсно-модуляцiйної спектроскопiї та описано їх еволюцiю пiд дiєю Х-опромiнення. Установлено величину граничної дози (D < 500 Ґр) перебудови ростових структурних дефектiв у кристалах p-Si за механiзмом Уоткiнса.

Changes of the defect structure of silicon p-type crystal surface layer under the influence of plastic deformation and high temperature annealing in oxygen atmosphere were investigated by deep-level capacitance-modulation spectroscopy (DLCMS) and IR spectroscopy of molecules and atom vibrational levels. Special role of dislocations in the surface layer of silicon during the formation of its energy spectrum and rebuilding the defective structure was established. It is shown that the concentration of linear defects (N ≥ 104 cm−2) enriches surface layer with electrically active complexes (dislocation-oxygen, dislocation-vacancy, and dislocation-interstitial atoms of silicon) which are an effective radiative recombination centers.

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