Conducting atomic force microscopy studies of InN nanocomposite layers having conducting and nonconducting phases

Conducting atomic force microscopy of InN layers grown by activated reactive evaporation method reveals that they are composed of conducting and nonconducting phases distributed at nanoscale. Deposition at higher substrate temperature or postdeposition annealing in nitrogen plasma results in an increase of the volume fraction of conducting phase, improved crystallinity of InN crystallites, shift in the absorption edge from 1.6 to 1.9 eV, and increase in the carrier concentration of InN nanocomposite layers. The nanocomposite nature of the InN layers and variation of parameters such as percent of high conducting phase and its distribution with process parameters explain the lack of direct relationship between the "measured" value of carrier concentration and shift in absorption edge, normally observed in poly/nanocrystalline InN layers.