Phonon plasmon interaction in ternary group-III-nitrides

Phonon-plasmon-coupling in the ternary group-III-nitrides InGaN and AlGaN is investigated experimentally and theoretically. Based on the observation of broadening and shifting of the A(1)(LO) mode in AlGaN upon Si-doping, a lineshape analysis was performed to determine the carrier concentration. The results obtained by this method are in excellent agreement to those from Hall measurements, confirming the validity of the employed model. Finally, neglecting phonon and plasmon damping, the Raman shift of the A(1)(LO) mode in dependence of the carrier concentration for AlGaN and InGaN is calculated. This enables a fast and contactless determination of carrier concentrations in the future. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739415]