Electron quasiconfinedopticalphonon interactions in wurtzite GaN/AlN quantum wells
Abstract
The equation of motion for the ppolarization field in a wurtzite GaN/AlN multilayer heterostructure is solved for the quasiconfinedopticalphonon modes based on the dielectriccontinuum model and Loudon's uniaxial crystal model. The polarization eigenvector, the dispersion relation of the quasiconfinedopticalphonon modes and the electronquasiconfinedphonon interaction Fröhlichlike Hamiltonian are derived. The analytical formulas can be directly applied to single/multiple quantum wells (QW's) and superlattices. The electronquasiconfinedphonon coupling functions are investigated for a given AlN/GaN/AlN single QW with full account of the strains of the QW structures and the anisotropy effect of wurtzite crystals. We find that there are two kinds of quasiconfinedopticalphonon modes in the GaN/AlN QW's: the GaNlayer quasiconfinedopticalphonon modes and the AlNlayer quasiconfinedopticalphonon modes. There are infinite quasiconfinedopticalphonon branches, labelled by a quantum number n (n=1,2,...), with definite symmetry with respect to the center of the AlN/GaN/AlN single QW for a given phonon wave number q. The dispersions of the quasiconfinedopticalphonon modes with smaller n are more obvious than the ones with larger n. Moreover, the modes with smaller n are much more important for their electronquasiconfinedphonon interactions than those with larger n. In most cases, it is enough to consider the modes with n≤ 8 for the electronquasiconfinedphonon interactions in a single GaN/AlN QW. The higher frequency modes are more significant than the lower ones. The longwavelength quasiconfinedopticalphonon modes are much more important for the electronquasiconfinedphonon interactions. The GaNlayer quasiconfinedopticalphonon energies and their electronquasiconfinedphonon interaction strength are markedly increased due to the strains of the QW structures. The influence of the strains on the the AlNlayer electronquasiconfinedphonon interactions can be ignored.
 Publication:

European Physical Journal B
 Pub Date:
 April 2005
 DOI:
 10.1140/epjb/e200500139x
 Bibcode:
 2005EPJB...44..401L
 Keywords:

 Neural Network;
 Anisotropy;
 Nonlinear Dynamics;
 Dispersion Relation;
 Frequency Mode