The influence of the central-cell potential on the higher excited acceptor states in ZnTe

Abstract

The effect of the central-cell potential on the higher excited states of acceptors (up to the sixth state) in ZnTe is considered using the Baldereschi-Lipari spherical model including the cubic correction. Results are obtained by solving the coupled radial equations by the finite-element method, which gives several low-lying states simultaneously for an arbitrary form of the potential. In the case of As-doped ZnTe, the calculation gives central-cell corrections of 19.1 meV for the 1S state and 2.2, 0.7 and 0.2 meV for the first, second and fifth excited S states, respectively. These values are to be compared with experimental values of 19.1, 3.5, 1.4 and 0.7 meV, respectively. This procedure permits the authors to determine the host band-structure parameters very accurately. For ZnTe they obtain the Luttinger parameters gamma 1=3.80, gamma 2=0.86 and gamma 3=1.30, and the dielectric constant epsilon 0=9.4.