Effect of nitridation on structure, electrical and optical properties of InN epilayers grown on sapphire by PAMBE

• InN epilayers were prepared on c-plane (0001) sapphire substrates by plasma-assisted MBE.
• The nitridation of the substrate impacted the qualities of InN flims.
• The energy band-gap of InN layers were found to be around 0.75–0.80 eV.

InN epilayers were prepared on c-plane (0001) sapphire substrates by plasma-assisted molecular beam epitaxy (PAMBE). We studied the effect of nitridation on structure, surface morphology, electrical and optical properties of InN films using X-ray diffraction (XRD), Reflection high-energy electron diffraction (RHEED), scanning electron microscopy (SEM), atomic force microscopy (AFM), Hall and photoluminescence (PL) measurement. The results showed a significant improvement of the crystalline qualities and surface morphologies and enhancement of the electrical and optical properties for InN films grown after nitridation. Moreover, the energy band-gap of InN films were also determined by optical absorption and photoluminescence (PL) measurement.