InN films with electron densities of 1.6 x 10(18)-1.4 x 10(19) cm(-3) had photoluminescence (PL) properties with clear electron density dependencies. The PL peak shifted to a higher energy with increasing electron density, whereas PL intensity decreased with increasing electron density. These characteristics are typical of degenerate semiconductors with a large density of defects and/or dislocations. We estimated a band-gap energy of 0.6-0.65 eV for intrinsic InN from the shift in the PL peak position and band-gap shrinkage due to the conduction-band renormalization effect. (C) 2004 Elsevier B.V. All rights reserved.