Growth atmosphere dependence of transport properties of NiO epitaxial thin films.

Recent possible applications in nonvolatile resistive switching memory devices renewed the interests in the transport properties of NiO. The variation on the conductivities of NiO films was reported to strongly affect the resistive switching phenomena. The conduction mechanism of NiO has been interpreted in terms of the bulk p-type conduction mechanism via Ni deficiencies (Ni1-δO). Here we investigate the growth atmosphere dependence on the transport properties of NiO thin films epitaxially grown on MgO (001) substrate. The conductivities of NiO thin films showed completely an opposite tendency compared to the bulk p-type conduction mechanism. Microstructural analysis demonstrates that the conductivity of low temperature grown NiO thin films strongly correlates with tailing the band edge via the deterioration of entire film crystallinity rather than the grain boundaries including second phases. [ABSTRACT FROM AUTHOR]