The Effect of Cr3+ and Mg2+ Impurities on Thermoluminescence and Deep Traps in β-Ga2O3 Crystals

Thermally stimulated luminescence (TSL) of beta-Ga2O3 single 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 beta-Ga2O3 with 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 E-1. Thus the Cr(3+)e(-) centers can be a candidate for E-1. 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 beta-Ga2O3 crystals 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. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.