Deep UV resonance Raman spectroscopic study on electron-phonon coupling in hexagonal III-nitride wide bandgap semiconductors

Electron-phonon coupling (EPC) is an important issue in semiconductor physics because of its significant influence on the optical and electrical properties of semiconductors. In this work, the EPC in wide bandgap semiconductors including hexagonal BN and AlN was studied by deep UV resonance Raman spectroscopy. Up to fourth-order LO phonons are observed in the resonance Raman spectrum of hexagonal AlN. By contrast, only the prominent emission band near the band-edge and the Raman band attributed to E-2g mode are detected for hexagonal BN with deep UV resonance excitation. The different behavior in resonant Raman scattering between the III-nitrides reflects their large difference in EPC. The mechanism for EPC in hexagonal BN is the short-range deformation interaction, while that in hexagonal AlN is mainly associated with the weak long-range Frohlich interaction. Copyright (c) 2016 John Wiley & Sons, Ltd.