New results are given of Raman scattering measurements on the dispersion characteristics of surface-phonon polaritons at the air-CaF, interface using the Otto configuration. A phenomenological description of the dispersion relation is also given theoretically as well. The experimental results are in good agreement with the theory. For comparison, the dispersion curve of the surfacephonon polariton under the same configuration is also measured by the ATR method in the infrared region and the agreement of the results from both the methods is also satisfactory. E s werden neue Ergebnisse aus Messungen der Ramanstreuung zu den Dispersionseigenschaften von Oberflachen-Phonon-Polaritonen an der Luft-CaF,-Grenzflache bei Anwendung der Otto-Iconfiguration angegeben. Eine phknomenologische theoretische Beschreibang der Dispersionsbeziehung wird ebenfalls angegeben. Die experimentellen Ergebnisse befinden sich in guter tfbereinstimmung mit der Theorie. Zum Vergleich wird die Dispersionskurve der Oberflachen-Phonon-Polaritonen mit der ATR-Methode unter derselben Konfiguration ebenfalls gemessen und die ifbereinstimmung der Ergebnisse beider Methoden ist ebenfalls befriedigend.
In this communication, we have carried out a detailed investigation of radiative recombination in n-GaAs homojunction far-infrared detector structures with multilayer emitter (n+)-intrinsic (i) interfaces by temperature-dependent steady-state photoluminescence measurements. The observation of the emitter-layer luminescence structures has been identified from their luminescence characteristics, in combination with high density theoretical calculation. A photogenerated carrier transferring model has been proposed, which can well explain the dependencies of the luminescence intensities on the laser excitation intensity and temperature. Furthermore, the obtained radiative recombination behavior helps us to offer a proposal to improve the operating temperature of the detector.
The Hamiltonian of the exciton in an ultrafine particle (UFP) with a charge on and a dipole at its surface is given. The exciton energy is calculated as a function of the charge number, the dielectric constant of the medium outside the UFP, and the strength of the dipole. The results for ZnO and CdS UFP indicate that the changes of the exciton energy due to the charge and the dielectric constant outside the UFP are of the same order.Der Hamilton-Operator eines Exzitons in einem ultrafeinen Teilchen (UFP) mit einer Ladung auf und einem Dipol an seiner OberflHche wird mitgeteilt. Die Exzitonenenergie wird als Funktion der Ladungszahl, der dielektrischen Konstanten des Mediums auoerhalb des UFP und der Dipolstarke berechnet. Die Ergebnisse fur ZnO und CdS zeigen, daO die Anderungen in der Exzitonenenergie aufgrund der Ladung und der dielektrischen Konstanten im auI3eren Medium von der gleichen Groljenordnung sind.
The present work deals with an electron interacting strongly with both bulk longitudinal optical (LO) phonons and interface (IF) optical phonons in which we adopt and generalize the Tokuda's variational method for studying the interface polaron properties in polar crystals at zero temperature. In our approach, we can reduce the Hamiltonian equation of the system to a pair of integro-differential equations in two variational parameters of the electron wavefunction from which we can calculate various physical properties of an interface polaron including the ground state energy, average numbers of interacting phonons, the average distance from the interface and the anisotropic effective masses of the interface polaron. Numerical results are obtained explicitly for LiF crystal interfaced with NaF crystal as well as other similar systems with varying physical constants, which show the typical trends of variations for the effects of strong electron-phonon interactions on different physical properties of an interface polaron.
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