The Effect of Cr3+and Mg2+Impurities on Thermoluminescence and Deep Traps in β-Ga2O3Crystals

Thermally stimulated luminescence (TSL) of β-Ga2O3single crystals doped with Cr3+and Mg2+impurities was investigated. Based on the correlation between the Cr3+concentration and light sum accumulated in the thermoluminescence (TL) glow peak at 285 K, it was concluded that doping of β-Ga2O3with Cr3+ions leads to the formation of electron traps manifested in this peak. The activation energy of peak at 285 K is equal to Ec-0.55 eV and close to E1. Thus the Cr3+e−centers can be a candidate for E1. The high-temperature TL glow peak at 385 K (Ec-0.94 eV) is related to oxygen vacancies which are created in gallium oxide doped by Mg2+ions to compensate for the negative charge formed by the substitution of gallium sites by magnesium ions.The co-doping of β-Ga2O3crystals with Cr3+and Mg2+impurities leads to the appearance of a new TL glow peak at 320 K with an energy close to E*2(Ec-0.7). It is suggested that this peak is formed by defect complex, in particular, oxygen vacancies with Cr3+or Fe3+ions.