Search for content and authors


Özden Akinci ,  Hikmet H. Gürel ,  Hilmi Ünlü 


We present a second nearest neighbor sp3 empirical tight binding study of alloy and pressure effects on the energy bands and band offsets in group II-VI semiconductor heterostructures. The resulting band structure for ZnSe/GaAs, ZnSSe/ZnSe, ZnCdTe/ZnTe and ZnCdSe/ZnSe, HgTe/CdTe and HgCdTe/CdTe heterostructures is analyzed using nonlinear tight binding parameters and bond lengths as a function of composition, interface lattice mismatch strain and external pressure. The model reproduces real band structure of all binaries at the , L and X points of the Brillouin zone. Using these parameters band offsets between ternary/binary II-VI compounds are calculated by screening the valence band energies with the optical dielectric constant function of composition, interface lattice mismatch strain and external pressure. It is gratifying to note that by screening of the valence band energy at point, the second nearest neighbor sp3 tight binding model describes very accurately the valence band offsets, in good agreement with experiment for many heterostructures. The model predicts that the growth orientation dependence of band offsets for lattice matched heterostructures is due to lattice thermal expansion difference across the interface and that in mismatched heterostructures is due to the change in sign of lattice mismatch strain. The electron-phonon interaction has very little effect on the valence band offsets but some effects on conduction band offsets as temperature is increased.


Legal notice
  • Legal notice:

Presentation: oral at E-MRS Fall Meeting 2004, Symposium H, by Hilmi Unlu
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-30 20:29
Revised:   2009-06-08 12:55