DISPERSION OF ACOUSTIC PHONONS IN QUASIPERIODIC SUPERLATTICES

The aim of this work is to present an up-to-date study of acoustic phonon excitations that can propagate in multilayered structure with constituents arranged in quasiperiodic fashion. In this paper, the dispersion relation of acoustic phonons for the quasiperiodic superlattice using different semiconducting materials, with the help of transfer matrix method, is derived at normal angle of incidence. Calculation is presented for (a) Ge / Si and (b) Nb / Cu semiconductor superlattices from 5th to 9th generations and dispersion diagrams are plotted using the famous Kronning–Penny model obtained from the transfer matrix of the structure. The concept of allowed and forbidden bands with the help of these dispersion curves in various generations of Fibonacci superlattices and the relation between imaginary value of propagation vector and the existence of forbidden bands is demonstrated.

Download Full-text

Analysis and Characterization of Surface Plasmon Enhancement of Light Absorption in Organic Solar Cells by the Transfer Matrix Method

Volume 4: Electronics and Photonics ◽

10.1115/imece2010-37393 ◽

2010 ◽

Author(s):

Francisco V. Rami´rez ◽

Amador M. Guzma´n

Keyword(s):

Solar Cells ◽

Transfer Matrix ◽

Organic Solar Cells ◽

Transfer Matrix Method ◽

Light Absorption ◽

Matrix Method ◽

Incident Light ◽

Thick Layer ◽

Physical Situation ◽

Angle Of Incidence

Surface plasmons enhanced light absorption in organic solar cells based on a photoactive poly(2-methoxyl-5-(2-ethyl-hexyloxy)-1.4-phenylenevinylene):(6.6)-phenyl-C61-butyric-acid-methylester (MEH-PPV:PCBM), is studied by a computational model based on the transfer matrix method (TMM). Two physical situation with and without the bulk heterojunction film are considered and modeled on a 2D array of silver nanoparticles with a diameter of 40 nm embedded in a 50-nm-thick layer. The numerical simulation results that include optical properties in the wave length range of 350 and 750 nm, present qualitative and quantitative good agreement with previous results obtained by Duche et al (2009) in both conditions. Optical absorption results for incident light at an oblique angle of incidence are also obtained, with the purpose of determining the effect of the angle of incidence on the absorption properties.

Download Full-text

Electronic properties of superlattices

Canadian Journal of Physics ◽

10.1139/p90-043 ◽

1990 ◽

Vol 68 (3) ◽

pp. 268-272 ◽

Cited By ~ 13

Author(s):

D. Aitelhabti ◽

P. Vasilopoulos ◽

J. F. Currie

Keyword(s):

Wave Function ◽

Dispersion Relation ◽

Band Structure ◽

Electronic Properties ◽

Transfer Matrix ◽

Current Density ◽

Transfer Matrix Method ◽

Matrix Method ◽

Tight Binding ◽

Effective Masses

Using the transfer-matrix method, we evaluate the exact normalized wave function analytically, the band structure, and the current density associated with an electron in a superlattice, with different or equal effective masses between wells and barriers. Also, we evaluate numerically the dispersion relation, the bandwidth, and the current density (in the tight-binding limit) for both equal and different effective masses between wells and barriers.

Download Full-text