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Dielectric properties of InAsP alloy thin films and evaluation of direct‐ and reciprocal‐space methods of determining critical‐point parameters
Author(s) -
Choi S. G.,
Aspnes D. E.,
Stoute N. A.,
Kim Y. D.,
Kim H. J.,
Chang Y.C.,
Palmstrøm C. J.
Publication year - 2008
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200777848
Subject(s) - reciprocal , reciprocal lattice , dielectric function , space (punctuation) , thin film , ellipsometry , alloy , point (geometry) , materials science , dielectric , analytical chemistry (journal) , spectral line , function (biology) , chemistry , mathematics , computational physics , condensed matter physics , physics , optics , nanotechnology , optoelectronics , computer science , quantum mechanics , geometry , composite material , philosophy , linguistics , operating system , chromatography , diffraction , biology , evolutionary biology
Spectroscopic ellipsometry is used to determine pseudodielectric function spectra 〈 ε 〉 = 〈 ε 1 〈 + i 〈 ε 2 〈 of InAs x P 1– x al‐loy thin films from 1.5 to 6.0 eV at room temperature. The structures for the E 1 , E 1 + Δ 1 , E ′ 0 , E 2 , and E ′ 2 critical points (CPs) were observed in the data. We compare direct‐ and reciprocal‐space methods of extracting CP energies E g . The direct‐space values show less uncertainty, a result of how the two procedures use available information. Energies obtained are compared with the results of theoretical calculations using the linear augmented Slater‐type orbital (LASTO) method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)