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Energy bands of , , and GaAs, calculated within the approximation. T and N correspond to X and L in the zincblende structure. (not shown) appears very similar to , except that the gap is larger. Colors signify orbital character of bands. Light dashed lines are LDA bands.
(Left) band gaps in (Zn,Cd)-IV-V CPs, calculated by . Pseudogaps and “true” gaps are shown as blue squares, and green circles. Lighter (darker) symbols are used for Zn (Cd)-bearing compounds. The fundamental gap is the smaller of and . This may be compared to experimental values, shown as horizontal bars. is approximately independent of cation ( for P compounds, and for As compounds). (Right) calculated absorption coefficient for , and . The transition from pseudodirect to direct absorption starting 2.1 eV is apparent in the case. GaAs is shown for comparison.
(Left) Conduction-band effective masses corresponding to direct gaps , calculated by . Light and dark symbols correspond to Zn and Cd compounds, respectively. Bottom panel plots a scaled mass, . (Right) Lattice constants (Å) and ratios in the II-IV-V CPs. LDA results are shown as green circles for comparison.
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