Anisotropic dielectric function spectra from single-crystal CuInSe2 with orientation domains

Abstract

The anisotropic optical constants of slightly In-rich CuInSe2 are determined on the (112) surface of a naturally grown single-crystal sample with orientation domains using generalized spectroscopic ellipsometry for photon energies between 0.8 and 4.5 eV. Orientation domains within the sample, revealed by electron diffraction investigation, cause biaxial response of the sample surface. The CuInSe2 dielectric functions are extracted at each wavelength rigorously considering orientation domains and surface roughness effects, and improve previous results.

Lattice dynamics and related properties of AIBIII and AIIBIV compounds, I. Elastic constants

“…The capability of the material to accommodate rather large deviations from stoichiometry and still to crystallise in the chalcopyrite structure finds its explanation in the formation of high concentrations of point defects (vacancies, antisite defects, interstitials) [77,78] and point defect complexes [13], extended structural defects (dislocations, stacking faults, twins) [78,79], orientation domains [80][81][82] separated by small angle grain boundaries [83], and microscopic inclusions of secondary phases in the chalcopyrite matrix [75,81,84]. As an additional complication it must be taken into account that, firstly, there are orientation domains with the CuAu-ordered structure [82] with lattice vibrational characteristics differing from those of the chalcopyrite lattice [85,86] and, secondly, the bond configurations at grain boundaries can considerably differ from the bonding properties in the bulk chalcopyrite matrix [87]. All these defects are expected to give rise to microscopic internal stress fields and corresponding more or less pronounced modifications of the vibrational properties of the compound in general and of the measured average elastic and mechanical properties of crystals in particular [88].…”

Optical properties and electronic structures of(4CuInSe2)y(CuHan1, Persson2, Hasoon3 et al. 2006Phys. Rev. B280183430View full textAdd to dashboardCite

“…[3][4][5][6][7][8][9] There have been studies of the optical properties relating to electronic structure of CIGS with different Ga compositions. [10][11][12][13][14] Anisotropy was present in bulk single-crystal CIGS 10-12 due to their chalcopyrite crystal structure with a tetragonal unit cell. CIGS exhibits uniaxial optical anisotropy, but bulk PX CIGSs except a CuGaSe 2 ͑CGS͒ specimen 13 and a thin-film PX CIGS specimen 14,15 displayed isotropic behaviors because the effective optical response is not anisotropic in thin-film PX CuInSe 2 ͑CIS͒ and PX CIGS.…”

Ellipsometry on Anisotropic Materials: Bragg Conditions and Phonons in Dielectric Helical Thin Films

“…Generalized Ellipsometry (GE), originally introduced by Azzam and Bashara [9], emerged recently as a new global approach for characterization of the optical and structural properties of general anisotropic layered materials, and can be applied for wavelengths from the far infrared to the deep ultra violet [6]. This technique, which provides normalized Jones reflection or transmission matrix elements [10], is very feasible for studying structural and dielectric properties of birefringent media [7,[11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”