Effect of periodic Si-delta-doping on the evolution of yellow luminescence and stress in n-type GaN epilayers

• Suppression of yellow luminescence in periodic Si-delta-doped GaN with increasing dopant flow rate or decreasing period length was observed.
• The weakening of yellow luminescence may be ascribed to the reduction of Ga vacancies by Si-delta-doping.
• Analysis of Raman spectroscopy indicated no obvious stress variation among samples with different equivalent electron concentration.

We report the effect of periodic Si-delta-doping on the yellow luminescence (YL) and stress evolution in n-GaN epilayers. Photoluminescence measurements indicated that the YL component could be effectively suppressed with increasing dopant flow rate or decreasing period length. X-ray diffraction, transmission electron microscopy and secondary ion mass spectroscopy measurements revealed that the variations of dislocation density and carbon concentration are not the responsible mechanisms for the of YL emissions. The reduction of Ga vacancy related defects seems to be the probable reason for the YL suppression by Si-delta-doping. Moreover, Raman spectroscopy showed no obvious stress variation among these samples with different equivalent electron concentration. These observed features are entirely different from those reported for uniformly Si-doped GaN.