We study the effects of electron-electron and electron-longitudinal optical (LO) phonon scatterings on the spectral lineshape and linewidth of intersubband transitions (ISBTs) within the second Born approximation. In particular, we show that there is a strong cancellation of the contributions from the so-called diagonal and nondiagonal scattering terms in the ISBT polarization equation to the linewidth. The omission of the nondiagonal scattering leads to a significant overestimate of the ISBT linewidth by several times for GaAs quantum wells. Such cancellation effect is less significant for semiconductors with strong nonparabolicity because of the dominance of the inhomogeneous broadening due to κ-dependent transitions. In addition, there is a cancellation effect between the electron-electron and electron-phonon scatterings, leading to a property of nonadditiveness of contributions from individual scattering processes to the linewidth. Finally, we compare our theoretical linewidth calculation with existing experimental measurements and very good agreement is achieved.
|Physical Review B - Condensed Matter and Materials Physics
|Published - Sep 2004
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics