Silicon doping of semipolar (112¯2)AlxGa1−xN(0.50≤x≤0.55)

• (112¯2)AlxGa1−xN(0.50≤x≤0.55) layers grown using different Si/III ratios.
• Achieved the highest carrier concentration/mobility of 1.2×1019 cm−3/30.7 cm2/V s.
• A strong correlation between the resistivity and luminescence emission intensities.
• Defect luminescence linked to impurities-charged cation vacancies and complexes.

The effect of silicon doping on the growth and properties of ∼1.0μm-thickAlxGa1-xN(0.50≤x≤0.55) layers grown on semipolar (112¯2)AlN templates by metalorganic vapour phase epitaxy was studied. The layers were grown with different disilane/group-III precursors ratios that varied from 2.8×10−5 to 3.4×10−4. The surface morphology of the Si-doped (112¯2)AlGaN layers showed undulations along [11¯00]AlGaN,AlN with a root-mean square roughness of about 4.0 nm within a scan range of 20×20μm2. Different photoluminescence peaks have been linked to negatively charged cation vacancies (VIII3−) and their complexes with impurities such as VIII3−-3ON1+, (VIII complex)1−, and (VIII complex)2−. The optimised AlGaN:Si layer exhibited a carrier concentration of ∼1.2×1019 cm−3, a carrier mobility of 30.7 cm2/V s, and a resistivity of 0.018Ωcm, as determined by Hall-effect measurements at room temperature. A correlation between the resistivity and luminescence emission intensities of AlGaN near-band-edge and impurity-related complexes was found.