One-dimensional electron-optical-phonon interaction Hamiltonians in a rectangular quantum wire consisting of diatomic polar semiconductors are derived under the macroscopic dielectric continuum model. The scattering rates calculated in a GaAs square quantum wire show that when the quantum wire is free-standing in vacuum, the interaction by the surface-optical phonon modes is very strong and may dominate over other scattering processes, especially with dimensions of about 100 Å or less. When the wire is embedded in a polar semiconductor (AlAs to be specific), the scattering rates by the surface-optical phonon modes become generally smaller, but yet comparable to those by the confined longitudinal-optical modes as the wire dimension shrinks. A considerable decrease in the total scattering rate for optical phonons as a result of simple reduction in dimensionality is not observed in this study.

The anharmonic decay of longitudinal-optical (LO) phonons in zinc-blende semiconductors has been studied. Based on an approach in which the anharmonic crystal potential is estimated using the theory of elasticity, the lifetime of LO phonons via emission of two acoustic phonons is calculated as a function of lattice temperature and phonon wave vector. Application of this model to bulk GaAs shows an excellent agreement with available experimental data. Since the parameters employed in the model can be obtained experimentally, the approach provides a useful tool to investigate LO-phonon lifetimes in semiconductors.

Based on a simplified analysis of perfectly conducting metals, it has been suggested qualitatively that establishing metal-semiconductor interfaces at the heterojunctions of polar semiconductor quantum wells introduces a set of boundary conditions that dramatically reduces or eliminates unwanted carrier energy loss caused by interactions with interface longitudinal-optical (LO) phonon modes. In this article, it is theoretically demonstrated that comparable reductions in LO phonon scattering strengths may be achieved for metal-semiconductor structures with metal having realistic conductivities and Thomas–Fermi screening lengths.

A simplified microscopic model of optical phonons in dimensionally confined structures is formulated and applied to calculate electronoptical-phonon scattering rates in GaAs/AlAs quantum wells. For this simplified model which circumvents performing a complicated ab initio calculation of the force constants at the interface, it is demonstrated that the resulting dispersion relation and scattering rates for electronoptical-phonon interactions agree very well with those obtained from detailed ab initio studies.

In this paper, the commonly used but idealistic formulation of quantized optical-phonon modes for a heterostructure system with only two heterojunctions (i.e., single quantum-well structures) is extended to the more realistic case of multiheterointerface structures. By applying the macroscopic dielectric continuum approach, dispersion relations and interaction Hamiltonians for interface-phonon modes are derived for a double-barrier structure and scattering rates based on these results are used to determine the range of practical validity of the idealistic model using interaction Hamiltonians appropriate for single quantum wells with infinite barrier widths. It is found that when the dimensions of the structures are larger than approximately 30 Å, this simplified description can be applied to multiheterointerface structures in general with reasonable accuracy.