Thermal activation of nitrogen acceptors in ZnO thin films grown by MOCVD

Abstract

Nitrogen doping in ZnO is inhibited by spontaneous formation of compensating defects. Perfect control of the nitrogen doping concentration is required, since a high concentration of nitrogen could induce the formation of donor defects involving nitrogen. In this work, the effect of post‐growth annealing in oxygen ambient on ZnO thin films grown by Metalorganic Chemical Vapor Deposition, using NO as both oxidant and nitrogen dopant, is studied. After annealing at 700 °C and above, low‐temperature photoluminescence shows the appearance of a transition at ∼3.23 eV which is interpreted as pair emission involving a nitrogen acceptor. A second transition at ∼3.15 eV is also discussed. This work suggests annealing as a potential means for p‐type doping using nitrogen (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Temperature-dependent photoluminescence of ZnO films codoped with tellurium and nitrogen

“…Admitting the above assignments and utilizing the energy relation between the FA and the FX transitions 31 the energy level of the acceptors E A is estimated to be $ 129 meV. This value is much shallower than the well accepted one ($200 meV) for the N O acceptors in ZnO materials, 32 but comparable to some reported E A values for codoped ZnO, 33,34 inferring that the form of acceptors in the Te-N codoped ZnO samples is not the simple N O substituting defect. The value of E A signifies a $ 0.7% activation rate of acceptors.…”

Effect of the annealing environment on the optical properties of ZnO/GaAs grown by MOCVD

“…Thus, this transition at $ 3.35 eV should be highly probable in samples with high concentrations of stacking faults. However, PL results on ZnO with intense stacking fault-related PL [20,23] do not show any line at $ 3.35 eV. Furthermore, the appearance of the PL line at 3.35 eV is obviously strongly dependent on the annealing ambient.…”