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Optical band gap in relation to the average coordination number in Ge—S—Bi thin films
Author(s) -
Saffarini G.,
Schmitt H.,
Shanak H.,
Nowoczin J.,
Müller J.
Publication year - 2003
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.200301821
Subject(s) - chalcogenide , coordination number , thin film , enthalpy of atomization , materials science , absorbance , band gap , vacuum evaporation , percolation (cognitive psychology) , chalcogenide glass , analytical chemistry (journal) , optics , chemistry , nanotechnology , optoelectronics , physics , composite material , ion , organic chemistry , chromatography , melting point , neuroscience , biology , enthalpy of fusion
Chalcogenide glasses belonging to the Ge x S 94 − x Bi 6 system (14 ≤ x ≤ 28.33 at%) have been prepared from high purity constituent elements. Thin films of the same materials have been deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as‐deposited films. The allowed optical transition is found to be indirect and the corresponding optical gaps, E g , are determined. The variation of E g with the average coordination number, 〈 r 〉, is also investigated. The observed E g − 〈 r 〉 dependence is discussed on the basis of the chemical bonding between the constituents and the rigidity percolation threshold behavior of the network.