Epitaxial growth of InN film by metalorganic chemical vapor deposition (MOCVD) is investigated with adding an InGaN bedding layer. The structure and optical properties of the InN film are in-vestigated by transmission electron microscopy (TEM) and photoluminescence (PL). From the se-lective area electron diffraction pattern in the TEM, the InN is found to be almost strain free. At low temperature of 8 K, strong PL of the InN film indicate that the energy band gap of the InN is about 0.75 eV. The anomalous persistent PL decay behavior under continuous-wave excitation has been observed and discussed as the surface recombination and strong surface/interface effect of the InN film. These results indicate that suppressing and eliminating surface/interface states is one of the key factors in enhancing the performance of the InGaN-based long-wavelength optoe-lectronic devices, which is significant for the development of efficient long-wavelength (red and beyond) InGaN or InN devices.
Chen et al. (Mon,) studied this question.