Determination of the carrier concentration in InGaAsNGaAs single quantum wells using Raman scattering

Abstract

Raman scattering from longitudinal optical phonon-plasmon coupled mode was observed in a series of InGaAsNGaAs single quantum well samples grown by metalorganic vapor phase epitaxy. The phonon-plasmon mode spectra were fitted with the dielectric constant function based on Drude model that contains contributions from both lattice vibrations and conduction electrons. The carrier concentration is calculated directly from the plasmon frequency, which is obtained from the fitting procedure. An empirical expression for the electron concentration, [n], in InGaAsNGaAs samples is determined as [n] ≈ {2.35× 1016 (ωm -502)} cm-3, where ωm is the peak of the upper frequency branch, L+, of the phonon-plasmon mode measured in unit of cm-1. The phonon-plasmon coupled mode was also investigated in rapid thermally annealed samples. © 2004 American Institute of Physics.