Determination of the carrier concentration in InGaAsN/GaAs single quantum wells using Raman scattering

摘要

Raman scattering from longitudinal optical phonon-plasmon coupled mode was observed in a series of InGaAsN/GaAs 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 InGaAsN/GaAs samples is determined as [n]≈{2.35×10~(16)(ω_(m)-502)}cm~(-3), where ω_(m) 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.