2020-02-15 19:04:37

责任者: Escorcia, R.A.;Riva, C.;Mikhailov, I.D. 单位: Dept. Natuurkunde, Univ. Antwerpen, Belgium 来源出处: Solid State Communications(Solid State Commun. (USA)),2004//,131(6):365-70 摘要: We investigate the effect of the longitudinal-optical phonon field on the binding energies of excitons in quantum wells, well-wires and nanotubes based on ionic semiconductors. We take into account the exciton-phonon interaction by using the Aldrich-Bajaj effective potential for Wannier excitons in a polarizable medium. We extend the fractional-dimensional method developed previously for neutral and negatively charged donors to calculate the exciton binding energies in these heterostructures. In this method, the exciton wave function is taken as a product of the ground state functions of the electron polaron and hole polaron with a correlation function that depends only on the electron-hole separation. Starting from the variational principle we derive a one-dimensional differential equation, which is solved numerically by using the trigonometric sweep method. We find that the potential that takes into account polaronic effects always give rise to larger exciton binding energies than those obtained using a Coulomb potential screened by a static dielectric constant. This enhancement of the binding energy is more considerable in quantum wires and nanotubes than in quantum wells. Our results for quantum wells are in a good agreement with previous variational calculations. Also, we present novel curves of the exciton binding energies as a function of the wire and nanotubes radii for different models of the confinement potential 关键词: aluminium compounds;binding energy;cadmium compounds;electric potential;gallium arsenide;ground states;II-VI semiconductors;III-V semiconductors;nanotubes;permittivity;phonon-exciton interactions;polarons;semiconductor heterojunctions;semiconductor quantum wells;semiconductor quantum wires;variational techniques;wave functions;wide band gap semiconductors;zinc compounds;polaronic exciton;quantum well wires;quantum wells;well nanotubes;exciton binding energy;ionic semiconductors;exciton phonon interaction;Aldrich-Bajaj effective potential;Wannier exciton;fractional dimensional method;exciton wave function;ground state functions;electron polaron;hole polaron;correlation function;electron hole separation;one dimensional differential equation;trigonometric sweep method;coulomb potential;static dielectric constant;variational principle;longitudinal-optical phonon field;quantum confinement potential;GaAs-GaAlAs;ZnSe-ZnCdSe