Effects of Mg and Si doping in the guide layers of AlGaN-based ultraviolet-B band lasers

•Effects of Mg and Si doping in the guide layers of UV-B lasers is discussed.•At the optimum Si doping concentration of 1018 cm−3.•When Si concentration was increased to 1019 cm−3, Γg decreased and αi increased.•With respect to Mg doping, Γg didn’t change up to about 1018 cm−3.•When Mg concentration was increased to 1019 cm−3, Γg decreased and αi increased.