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Intrinsic Optical Properties of CrCl 3
Author(s) -
Pollini I.,
Spinolo G.
Publication year - 1970
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.19700410224
Subject(s) - photoconductivity , photocurrent , crystal (programming language) , absorption edge , materials science , anisotropy , absorption (acoustics) , octahedron , refractive index , absorption spectroscopy , analytical chemistry (journal) , molecular physics , optics , chemistry , crystallography , crystal structure , optoelectronics , band gap , physics , chromatography , computer science , programming language , composite material
The intrinsic optical absorption spectrum of CrCl 3 has been investigated in the 0.6 to 6 eV region at temperatures from 80 to 300 °K. A careful analysis of the crystal field bands in the 0.6 to 3 eV region has revealed some structures and details, such as an Urbach's rule edge, not previously reported. The optical anisotropy of CrCl 3 was also studied over the same spectral range. In the region between 3 and 8 eV reflectivity spectra were also obtained. The refractive index of CrCl 3 has been determined on evaporated films from 1000 to 380 nm [ n (500nm) = 1.85 ± 0.1]. The spectral distribution of photocurrent at ≈ 80 °K was measured and showed weak peaks associated with the main crystal field bands and a sharp increase at shorter wavelengths; maximum photoconductivity yield was reached at (3.2 ± 0.2) eV. The data on the crystal field bands are discussed and some new structures are assigned to specific electronic transitions. Account is taken of the spin—orbit interaction among the various multiplets and the trigonal distortion of the octahedral symmetry of the Cr 3+ environment. A discussion of the optical and photoconductivity data in the 3 to 8 eV region is given and alternative explanations of the absorption edge at 3.2 eV are proposed.