Preparation and characterization of hexagonal MnTe and ZnO layers

MnTe layers of high crystalline quality were grown on Al2O3 substrates (0001)-oriented by molecular beam epitaxy (MBE). Characterization of MnTe by X-ray diffraction (XRD) revealed a hexagonal structure of NiAs-type with lattice parameters a = 4.166 A and c = 6.694 A. The energy gap of MnTe, evaluated from the optical transmission spectra measured at 10 K, was found to be 1.7 eV. The Neel temperature obtained from neutron diffraction (ND) measurements was 284.1 K. ZnO:N layers were fabricated by thermal oxidation of metallic Zn and ZnTe grown by MBE on different substrates. In order to achieve p-type conductivity, the starting materials were doped by nitrogen. The XRD spectra of the oxidized samples showed peaks related to hexagonal ZnO. The Hall measurements demonstrated p-type conductivity with the hole concentration of ∼2.2 × 1019 cm–3 and ∼6.7 × 1017 cm–3 for ZnO:N deposited on GaAs and ZnTe, respectively. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)