Sol-gel spin coating growth of magnesium-doped indium nitride thin films

We report on sol-gel spin coating growth of magnesium (Mg)-doped indium nitride (InN) thin films with different Mg concentrations (i.e., 0%-4%). Polycrystalline films with wurtzite structure and preferred orientation of InN (101) are obtained. Field emission scanning electron microscope results reveal that InN thin films doped with 2% Mg exhibit hexagonal symmetry grains. The elemental composition analysis demonstrates that all samples are formed with approximately 1:1 atomic percentage ratio of indium to nitrogen. With regard to Raman measurements, a weak local vibration mode of Mg-N is detected at 562 cm−1. This condition implies that Mg atoms are successfully incorporated into InN. Hall Effect measurements show that InN films doped with 1% and 2% Mg exhibit p-type conductivity, and the other samples show n-type conductivity. These results suggest that the low-cost sol-gel spin coating can be a potential method to synthesize p-type InN films.