A study on electrical transport vis-à-vis the effect of thermal annealing on the p-type conductivity in arsenic-doped MOCVD grown ZnO in the temperature range 10–300K

摘要: Abstract Arsenic-doped p-type ZnO films were grown by MOCVD on semi-insulating GaAs substrates followed thermal annealing. In order to study the dependence of charge transport doping concentration, carrier concentration in varied varying post-deposition annealing temperature. The doped showed conductivity at room temperature with 4.5 × 10 18  cm −3 (Sample A), 2.8 × 10 19 B) and 5.7 × 10 C) annealed, respectively, 650 °C, 700 °C 750 °C oxygen ambient. To investigate dependent mechanism films, dc has been measured over a wide range from 300 K down 10 K. experimental data for found follow Mott’s variable hopping (M-VRH) type conduction lower region, whereas, higher region is governed thermally activated (TA) band conduction. It that sample A, M-VRH observed 10–52 K whereas this upper-end reduced when samples are annealed temperatures. Thus B C, 10–41 K 10–35 K, respectively. On other hand, TA 130–300 K, 116–300 K 110–300 K decrease onset increase due high density acceptor impurity levels close valence band, which facilitates comparatively average distance between localized states near Fermi level low temperatures small facilitating transport.