Abstract
Spectroscopic ellipsometry (SE) has been performed to determine the optical properties of the InN epitaxial films grown by nitrogen-plasma-assisted molecular-beam epitaxy on Si(111) substrates using a double-buffer technique. In addition to SE, cross-sectional transmission electron microscopy and x-ray diffraction reveal that epitaxially grown InN epilayer is homogeneous with high crystalline quality and does not include any metallic In. SE results analyzed by the Adachi's model for the dielectric function of InN show that the optical absorption edge of InN varies in the range of 0.76-0.83 eV depending on the carrier concentration, which is determined by the thickness of the AlN buffer layer. © 2005 American Institute of Physics.