Magnesium doped semipolar (11–22) p-type gallium nitride: Impact of dopant concentration variants towards grain size distributions and crystalline quality

Abstract

In this study, the effect of biscyclopentadienyl magnesium flow rate for the growth of p-type gallium nitride thin films was varied from 20 to 40 standard cubic centimeter per minute to acquire the optimum doping concentration level. The growth of semi-polar (11–22) p-type gallium nitride thin films on m-plane sapphire was accomplished via metal organic chemical vapor deposition. Atomic force microscopy reveals the occurrence of dissimilar grain size distributions upon the utilization of different dopant flow rates. Statistical data shows that the utilization of optimized biscyclopentadienyl magnesium flux of 30 standard cubic centimeter per minute would significantly reduce the grain size to as low as ∼ 550 nm (±1 nm), yielding a root mean square roughness of 6.00 nm. X-ray rocking curve analysis observed that a moderate biscyclopentadienyl magnesium flow rate of 30 standard cubic centimeter per minute leads to narrowing in full width at half maximum, indicating an enhanced crystallinity with a reduction of the basal stacking fault density of 8.18 × 104 cm−1 with the use of 30 standard cubic centimeter per minute of biscyclopentadienyl magnesium. Moreover, the mobilities and carrier concentrations were improved to as high as 1.8 cm2.V − 1.s − 1 and 5.5 × 1017 cm−3 with a moderate biscyclopentadienyl magnesium flow rate of 30 standard cubic centimeter per minute. The analysis suggests that with the optimum biscyclopentadienyl magnesium flow rate (30 standard cubic centimeter per minute), preferential sites for magnesium incorporation can be enhanced.