Table 1
Adjusted form factors (in Ry) for the studied binaries.
| Material | VS (3) | VS (8) | VS (11) | VA (3) | VA (4) | VA (11) |
|---|---|---|---|---|---|---|
| ZnS | −0.273609 | 0.041552 | 0.057521 | 0.207435 | 0.14000 | 0.04000 |
| CdS | −0.381411 | 0.068308 | −0.238828 | 0.311320 | 0.13000 | 0.223786 |
| ZnSe | −0.283115 | 0.056426 | 0.033312 | 0.178871 | 0.12300 | 0.053152 |
| CdSe | −0.293661 | 0.017887 | −0.156928 | 0.260615 | 0.12000 | 0.152888 |
| MgSe | −0.241454 | 0.026 | 0.05 | 0.15 | 0.089 | −0.03 |
Table 2
Calculated and experimental energy gaps for the binary compounds.
| Material | a [a.u.] | EΓΓ | [eV] | EΓX | [eV] | EΓL | [eV] |
|---|---|---|---|---|---|---|---|
| Calc. | Exp. | Calc. | Exp. | Calc. | Exp. | ||
| ZnS | 10.224d | 3.51a | 3.70b | 5.23a | 5.20b | 5.28a | 5.30b |
| CdS | 11.021d | 2.69a | 2.50b | 6.00a | 6.00b | 5.67a | 5.60b |
| ZnSe | 10.711d | 2.68a | 2.80b | 4.49a | 4.50b | 4.47a | 4.50b |
| CdSe | 11.484d | 2.01a | 1.90b | 5.41a | 5.40b | 4.74a | 4.70b |
| MgSe | 11.130d | 4.21a | 4.21c | 4.13a | 4.05c | 4.19a | 4.19c |
d [2]
b [12]
b [12]
b [12]
d [2]
b [12]
b [12]
b [12]
d [2]
b [12]
b [12]
b [12]
d [2]
b [12]
b [12]
b [12]
d [2]
c [16]
c [16]
c [16]
Electronic band structure in zinc-blende (zb) phase for: (a) Zn0.5Cd0.5S, (b) Zn0.5Cd0.5Se, (c) ZnS0.5Se0.5, (d) Mg0.5Zn0.5Se.
Variation of energy gap with concentration for ZnxCd1−xS in zb phase, obtained with VCA (dashed lines) and improved VCA (solid lines).
Variation of energy gap with concentration for ZnxCd1−xSe in zb phase, obtained with VCA (dashed lines) and improved VCA (solid lines).
Variation of energy gap with concentration for ZnSxSe1−x in zb phase, obtained with VCA (dashed lines) and improved VCA (solid lines).
Variation of the energy gap with concentration for MgxZn1−xSe in zb phase, obtained with VCA (dashed lines) and improved VCA (solid lines).
Table 3
Bowing parameters for the energy gaps EΓΓ, EΓX, EΓL within improved VCA.
| p | EΓΓ [eV] | EΓX [eV] | EΓL [eV] | |
|---|---|---|---|---|
| ZnxCd1−xS | 1.05a | 0.848a, 0.827b | 0.077a | 0.725a |
| ZnxCd1−xSe | 1.205a | 0.384a, 0.387b | −1.023a | −1.075a |
| ZnSxSe1−x | 0.28a | 0.595a, 0.580b, 0.46d | 0.548a | 0.516a |
| MgxZn1−xSe | 0.34a, 0.72c | 0.600a, 0.600b, 0.4c | −0.718a | −0.634a |
b [2]
b [2]
b [2]
d [17]
c [14]
b [2]
c [14]
Variation of refractive index as a function of concentration x for ZnxCd1−xS, obtained with VCA (dashed lines) and improved VCA (solid lines).
Variation of refractive index as a function of concentration x for ZnxCd1−xSe, obtained with VCA (dashed lines) and improved VCA (solid lines).
Variation of refractive index as a function of concentration x for ZnSxSe1−x, obtained with VCA (dashed lines) and improved VCA (solid lines).
Variation of refractive index as a function of concentration x for MgxZn1−xSe, obtained with VCA (dashed lines) and improved VCA (solid lines).