Disproportionation and comproportionation reactions of resistive switching in polycrystalline NiOx films

Abstract

Articles you may be interested inNickel vacancy behavior in the electrical conductance of nonstoichiometric nickel oxide film Reproducible resistive switching in nonstoichiometric nickel oxide films grown by rf reactive sputtering for resistive random access memory applications NiO x thin film exhibited excellent bistable unipolar resistive switching ͑RS͒, which has a high potential in nanoscale nonvolatile-memory applications. The underlying reaction of RS in NiO x is still in debate. We studied the chemical bonding states of Ni 2p and O 1s at high/low resistance spots using focused x-ray photoelectron spectroscopy. The disproportionation and comproportionation reactions of 3NiO↔ Ni+ Ni 2 O 3 accounted for the RS of NiO x . The calculated Gibbs energy of the reaction interpreted its reversibility in thermodynamics. The expansion and contraction of the filaments with switching were observed by conducting atomic force microscopy.

Magnetoresistance Behavior of Conducting Filaments in Resistive-Switching NiO with Different Resistance States

“…30 These Ni ions result from breaking of Ni bonds 45,48 in the Ni filaments, and the O ions result from the thermal decomposition effect of surrounding oxygen-rich clusters such as Ni 2 O 3 produced in the SET process. 24,44 On the basis of the preceding scenario for the RESET process, we can explain the strong correlation between sign of the AMR ratio and RRR value of the HRS as follows. We have shown that the size of Ni filament in NiO films varies over a large range in this work, and it was reported in the literature that higher temperature due to Joule heating is needed to reset the Ni conducting filaments with relatively large diameters.…”

“…47 Therefore, the migration of Ni ions during the RESET process should be considered, which has been neglected in previous work. 23,24,44 We propose the following scenario for the RESET process. The current through Ni filaments leads to Joule heating, which makes Ni ions migrate out of the hot region (Ni filaments) and oxygen ions migrate in the reverse direction.…”

“…So far, the nature of the RESET process in the NiO film has not yet been completely elucidated . Most researchers believe that the RESET process is caused by oxygen ion migration-induced reoxidation of the conducting filaments ,,, without considering the migration of Ni ions. However, for the oxidation of Ni, it has been well established both experimentally and theoretically that, below 800 °C, the outward diffusion of Ni ions (produced due to ionization at the interface) through the NiO formed around Ni is the dominant transport process , with a slight inward diffusion of oxygen ions, while over 800 °C, oxygen ion transport also has to be taken into consideration .…”

Symproportionation versus Disproportionation in Bromine Redox Systems

“…This paper concerns two opposite processes involved with redox reactions, named as disproportionation [1] (dismutation [2]), and symproportionation [3][4][5] (also known as synproportionation [6], conproportionation [7][8][9][10] comproportionation [11,12]) reactions, see [13]. The adjective "proportionate" means "being in proper proportion", or "degree when considered in relation to something else" [14].…”

Enhanced Oxidation of Nickel at Room Temperature by Low-energy Oxygen Implantation

“…[21] However, in the case of Ni oxides, this peak has also been assigned to the emission from the Ni2O3 phase that can be present at low concentration within the NiO films. [25] A possible contribution from a Ni2O3 phase in the Ni 2p3/2 spectrum is difficult to distinguish within the signal dominated with NiO phase, as the BE of Ni-O bonds in Ni2O3 overlap with the multiplet splitting structure of NiO (peak 3 from Figure 2). [15,26] Although in the present paper we only discuss the formation of a NiO phase, the presence of a small concentration of Ni2O3 phase should also be anticipated within the total concentration of Ni oxide.…”