Figure - available from: APL Materials
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(a) Theoretically predicted³⁰ and (b) experimentally determined bond lengths of (Ag,Cu)GaSe2 as a function of Ag/(Ag + Cu) ratio and (c) experimental bond lengths of Cu(In,Ga)Se2³¹ as a function of In/(In + Ga) ratio, shifted by 0.005Å for consistency. The uncertainty of the bond lengths is 0.003Å and is, thus, smaller than the symbol size. The dashed lines in panel (a) are a guide to the eye, whereas the solid lines in panels (b) and (c) represent the model fits based on the valence force field plus the law of mass action approach.³² The uncertainty of these model fits is indicated by the shaded areas and is mainly due to the uncertainties of the bond lengths, literature force constants, and extrapolation of the lattice constants to low temperatures. Note the break in the y axes.
Source publication
Contrary to other semiconductor alloys, incorporation of Ag into CuGaSe2 increases the bandgap, even though the lattice expands, and the Ga–Se bond length is theoretically predicted to decrease rather than increase. Herein, we experimentally confirm this peculiar bond length dependence of (Ag,Cu)GaSe2 using x-ray absorption spectroscopy. We further...
