Abstract
The thermally evaporated stoichiometric CdI2 films show goodc-axis alignment normal to substrate plane for film thickness up to 200 nm. The optical absorption data indicate an allowed direct interband transition across a gap of 3.6 eV in confirmation with earlier band structure calculations. However, part of the absorption data near band edge can be fitted to an indirect band gap of 3 eV. The dependence of band gap on film thickness (> 200 nm) can be explained qualitatively in terms of decreasing grain boundary barrier height with grain size.
References
Bordas J, Robertson J and Jakobsson A 1978J. Phys. C: Solid State Phys. 11 2607
Brahms S 1965Phys. Lett. 19 272
Bringans R D and Liang W Y 1981J. Phys. C: Solid State Phys. 14 1065
Coehoorn R, Sawatzky G A, Haas C and deGroot R A 1985Phys. Rev. B31 6739
Cullity B D 1978Elements of X-ray diffraction (California, USA: Addison-Wesley) 2nd Ed. p. 102
Greenaway D L and Nitsche R 1965J. Phys. Chem. Solids 26 1445
Hulliger F, Levy F and Reidel D 1976 inStructural chemistry of layer-type phases (Dordrecht, Holland: Ed. publishing company) pp 31–34 and 275
Kondo S, Matsuoka S and Saito T 1994Phys. Status Solidi (b) 186 K77
Kondo S, Matsuoka S and Saito T 1998aPhys. Status Solidi (a) 165 271
Kondo S, Suzuki T and Saito T 1998bJ. Phys. D: Appl. Phys. 31 2733
Lee P A, Said G, Davis R and Lim T H 1969J. Phys. Chem. Solids 30 2719
McCanny J V, Williams R H, Murray R B and Kemeny P C 1977J. Phys. C: Solid State Phys. 10 4255
Mott N F and Davis E A 1979Electronic processes in non-crystalline materials (Oxford: Clarendon Press) pp. 273–274
Nakagawa H, Yamada T, Matsumoto H and Hayashi T 1987J. Phys. Soc. Jap. 56 1185
Pollini I, Thomas J, Coehoorn R and Hass C 1986Phys. Rev. B33 5747
Robertson J 1979J. Phys. C: Solid State Phys. 12 4753
Slater J C 1956Phys. Rev. 103 1631
Takemura Y, Komatsu T and Kaifu Y 1975Phys. Status Solidi (b) 72 K87
Trigunayat G C 1991Solid State Ionics 48 3
Yu R M 1967Philos. Mag. 16 1167
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Tyagi, P., Vedeshwar, A.G. Grain size dependent optical band gap of CdI2 films. Bull Mater Sci 24, 297–300 (2001). https://doi.org/10.1007/BF02704925
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DOI: https://doi.org/10.1007/BF02704925