Carrier dynamics and related electronic band properties of InN films

Abstract

In the present article, we focus our discussion on the carrier dynamics of the scattering and recombination processes of InN films and the related band-edge energy structure. Various reports on this matter are summarized and some issues are reexamined. The analysis result based on the apparent band-band transition matrix element is consistent with a reported effective heavy hole mass of 0.59 (±0.06) m0. An Ep value related to the transition matrix element of 10-14 eV is thought to be plausible. The ambiguity of the band-edge structure is evaluated by the uncertainty of electron density. The distortion of the conduction band bottom and the ambiguity of the estimation of the many-body effect are discussed. The enhancement of the anisotropic electron-scattering nature with the decrease in residual electron density reveals that the residual electron source has isotropic potentials: point defects or small complexes. Infrared reflectance spectrum analysis reveals the high electron mobility inside grains in spite of the scattering by edge-type dislocations which cause the anisotropic carrier scattering. The recombination processes at low temperatures are dominated by nonradiative processes related to edge-type dislocations, while the thermally activated nonradiative recombination process is independent of the dislocation density. The activation processes and energies of the recombination related to phonon localization are characterized. InN is a peculiar material that has high carrier mobility and a strong electron-phonon interaction, which possibly induces the high nonradiative carrier recombination rate. The control of phonon localization is thus required.