The Effect of Cr 3+ and Mg 2+ Impurities on Thermoluminescence and Deep Traps in β-Ga 2 O 3 Crystals

Abstract

Thermally stimulated luminescence (TSL) of β -Ga 2 O 3 single crystals doped with Cr 3+ and Mg 2+ impurities was investigated. Based on the correlation between the Cr 3+ concentration and light sum accumulated in the thermoluminescence (TL) glow peak at 285 K, it was concluded that doping of β -Ga 2 O 3 with Cr 3+ 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 Mg 2+ ions to compensate for the negative charge formed by the substitution of gallium sites by magnesium ions.The co-doping of β -Ga 2 O 3 crystals with Cr 3+ and Mg 2+ 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 Cr 3+ or Fe 3+ ions.