Optical Properties of Electronic Materials: Fundamentals and Characterization

Determination of Optical Properties of Undoped Amorphous Selenium (a-Se) Films by Dielectric Modeling of Their Normal-Incidence Transmittance Spectra

“…A common approach is the indirect (inverse) synthesis technique { , }⟶{ , }, which is based on inserting multi-constant dispersion function for and (Tan, 2006;Tan et al, 2007;Tan et al, 2006;Theiss, 2012;Forouhi & Bloomer, 1986;Forouhi & Bloomer, 1988;Adachi, 1991;Jellison & Modine, 1996;Chambouleyron & Martínez, 2001;Truong & Tanemura, 2006;Kasap & Capper, 2006;Christman, 1988;Rogalski & Palmer, 2000;Palik, 1998;Dressel & Grüner, 2002;Reitz et al, 1993) into theoretical formulas of transmittance and/or reflectance of a multi-layered structure including the film, and then use a powerful statistical curve-fitting program to attain simulated transmittance and reflectance curves to the entire and data (Solieman et al, 2014;Navarrete et al, 1990;Solieman & Abu-Sehly, 2010;Joo et al, 1999;Dobrowolski et al, 1983;Klein et al, 1990;Kukinyi et al, 1996;Chiao et al, 1995;Theiss, 2012). Numeric inversion approaches, armed with dielectric models, are also used for analyzing optical data acquired from spectroscopic ellipsometry, which are based on measured polarized-light reflection quantities of a structure that are directly related its optical functions.…”

“…The full theoretical formulations for specular transmittance and reflectance of multi-layered structures at which monochromatic light waves are obliquely incident and the mathematical approaches used to derive them are discussed in detail in a variety of scientific reviews and advanced books (Richards, 1998;Chambouleyron & Martínez, 2001;Truong & Tanemura, 2006;Kasap & Capper, 2006;Palik, 1998;Dressel & Grüner, 2002;Reitz et al, 1993;Jackson, 1998;Born & Wolf, 2002;Jafar, 2013;Nichelatti, 2002;Dresselhaus, 2001) and in Appendix A.…”

“…If the slab has thickness , smooth, homogenous surfaces, complex index of refraction , and is sufficiently thick (incoherent) such that ∆ ≫ λ /2 , light intensities of back and forth light-wave reflections at its internal interfaces with air (v) of ≅ 1.0 0 can be added algebraically (incoherently) to give expressions for its specular reflectance and transmittance of the form (Richards, 1998;Richards et al, 2004;Theiss, 2012;Chambouleyron & Martínez, 2001;Truong & Tanemura, 2006;Kasap & Capper, 2006;Palik, 1998;Dressel & Grüner, 2002;Reitz et al, 1993;Jackson, 1998;Born & Wolf, 2002;Jafar, 2013;Nichelatti, 2002;Dresselhaus, 2001) …”

“…Only when a global minimum solution for the curve-fitting problem is achieved, one obtains reliable and informative dielectric and optical parameters for the studied film. If the substrate in the {air/thin uniform film/thick substrate/air}-stacking is transparent ( ≅ 0) in the spectral region above the absorption edge of the film, the -formula given in Equation (4) reduces to a wieldy expression that forms the basis of the analytical envelope and PUMA methods (Birgin et al, 1999;Mulato et al, 2000;Erarslan & Gungor, 2010;Ventura et al, 2005;Manifacier et al, 1976;Swanepoel, 1983;Minkov, 1990;El-Naggar et al, 2009;Epstein et al, 1987;González-Leal et al, 1998;Tigau, 2006;Poelman & Smet, 2003;Swanepoel, 1984;Chambouleyron & Martínez, 2001;Truong & Tanemura, 2006;Kasap & Capper, 2006), the application of which do not necessitate in prior dispersion functions for the film's optical constants.…”

“…Classically, electrons and nuclei of atoms in dielectrics and undoped semiconductors as well as ion pairs in ionic substances are visualized to be pushed apart (slightly) by the force caused by a weak externally applied electrostatic field; thus, forming a collection of microscopic electric dipoles, the resultant of which gives rise to a net electric dipole moment or macroscopic polarization inside the sample-that is, the sample becomes electrically polarized. The permanent electric dipoles in a polar solid, however, are more or less free to rotate and will be re-oriented under the action of both of the applied electric field and thermal agitations, with the resulting orientational electric polarization being strongly dependent on ambient temperature of the polar solid, whereas the field-induced shifts of electrons bounded to its atoms relative to their respective nuclei result in a temperature-independent electronic (deformation) polarization (Tan, 2006;Tan et al, 2007;Tan et al, 2006;Chambouleyron & Martínez, 2001;Truong & Tanemura, 2006;Kasap & Capper, 2006;Christman, 1988;Rogalski & Palmer, 2000;Palik, 1998;Dressel & Grüner, 2002;Reitz et al, 1993;Jackson, 1998;Born & Wolf, 2002). On the contrary, response of a metal under the action of an electrostatic field is quite different and electrons (holes) are envisioned to be expelled out of its interior.…”