RESONANT EXCITATION OF INTRINSIC AND SHALLOW TRAP LUMINESCENCE IN MOVPE GROWN ZNTE LAYERS

We present high resolution spectra of excitons, shallow donors and acceptors in ZnTe epilayers grown on GaAs and GaSb by atmospheric pressure metal-organic vapor-phase epitaxy (MOVPE). Resonant excitation made the observation of selective-pair luminescence (SPL), two-electron transitions (TET) and two-hole transitions (THT) possible. The investigation of donor states in I-doped layers yields m(e)* = 0.117m0 and a static dielectric constant epsilon(st) = 9.4. The Luttinger parameter gamma-1 = 3.8 was obtained from 1s- and 2s-free exciton transitions. As-acceptor states were observed in strain-free layers. A fit to calculations of Baldareschi and Lipari leads to gamma-2 = 0.72 and gamma-3 = 1.3. Level shift and splitting in magnetic fields corroborated the present assignments. The magnetic parameters kappa(A) = -0.27 and q(A) = -0.015 were obtained from As-acceptor bound excitons and the first excited acceptor state.