Abstract
The interaction between chemisorbed oxygen adatoms (O(2(ad))(-)) and oxygen vacancies associated with the formation/rupture of conductive filaments dominates the switching yield of ZnO, which is also confirmed by the fact that the reduction of SET/RESET voltage with the temperature. The pronounced surface effect-induced conductivity lowering due to (O(2(ad))(-)) chemisorption leads to increased resistance of high resistance state (HRS). The current decay of the HRS with increased temperatures/times is owing to the severe (O(2(ad))(-)) chemisorption as Joule heating is continuously applied. The statistical analysis for over 400 cells provides essential evidence for evaluating the surface effect on resistive switching. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3659296]