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.

中文翻译：

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β-Ga2O3：Cr3 +和β-Ga2O3：Cr，Mg单晶的电导率与发光性能的相关性

光致发光，激励，并且吸收光谱以及的β-Ga的电导率₂ ö ₃：Cr和的β-Ga ₂ ö ₃：的Cr，Mg的单晶进行了研究。在生长态的β-Ga ₂ ö ₃：铬晶体具有绿色，在约10的电导率^-2 -10 ^-3  Ω ^-1 厘米^-1，和Cr的低屈服³⁺杂质的发光。氧气气氛中的退火导致Cr ³⁺红色发光产量的大幅增加，电阻率的增加以及吸收光谱和激发光谱的变化。同样，Cr ^3+的增加的β-Ga的共掺杂后的发光率和电阻率，观察₂ ö ₃与镁（Mg铬晶体：²⁺）。Cr ³⁺发光产率，电导率以及吸收光谱和激发光谱中所记录的变化被认为是由于费米能级的变化。在AS-生长的β-Ga ₂ ö ₃：铬晶体，费米能级位于靠近导带的底部，和最铬离子是在Cr ²⁺电荷状态。在氧气气氛中进行退火以及将晶体与铬和镁杂质共掺杂，使费米能级移向带隙的中间，并使铬离子重新充入铬³⁺状态。