Limits...
Forming-free bipolar resistive switching in nonstoichiometric ceria films.

Ismail M, Huang CY, Panda D, Hung CJ, Tsai TL, Jieng JH, Lin CA, Chand U, Rana AM, Ahmed E, Talib I, Nadeem MY, Tseng TY - Nanoscale Res Lett (2014)

Bottom Line: X-ray photoelectron spectroscopy study confirmed the presence of oxygen vacancies in both of the said regions.In the low-resistance ON state, the electrical conduction was found to be of ohmic nature, while the high-resistance OFF state was governed by trap-controlled space charge-limited mechanism.The stable resistive switching behavior and long retention times with an acceptable resistance ratio enable the device for its application in future nonvolatile resistive random access memory (RRAM).

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu 30010, Taiwan. tseng@cc.nctu.edu.tw.

ABSTRACT
The mechanism of forming-free bipolar resistive switching in a Zr/CeOx/Pt device was investigated. High-resolution transmission electron microscopy and energy-dispersive spectroscopy analysis indicated the formation of a ZrOy layer at the Zr/CeOx interface. X-ray diffraction studies of CeOx films revealed that they consist of nano-polycrystals embedded in a disordered lattice. The observed resistive switching was suggested to be linked with the formation and rupture of conductive filaments constituted by oxygen vacancies in the CeOx film and in the nonstoichiometric ZrOy interfacial layer. X-ray photoelectron spectroscopy study confirmed the presence of oxygen vacancies in both of the said regions. In the low-resistance ON state, the electrical conduction was found to be of ohmic nature, while the high-resistance OFF state was governed by trap-controlled space charge-limited mechanism. The stable resistive switching behavior and long retention times with an acceptable resistance ratio enable the device for its application in future nonvolatile resistive random access memory (RRAM).

No MeSH data available.


Related in: MedlinePlus

I-V curves of the Zr/CeOx/Pt memory device are displayed in double-logarithmic scale. The linear fitting results in both ON state and OFF state: (a) positive-voltage region and (b) negative-voltage region. The corresponding slopes for different portions are also shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3927661&req=5

Figure 8: I-V curves of the Zr/CeOx/Pt memory device are displayed in double-logarithmic scale. The linear fitting results in both ON state and OFF state: (a) positive-voltage region and (b) negative-voltage region. The corresponding slopes for different portions are also shown.

Mentions: In order to elucidate the conduction mechanisms of the device, the I-V curve is plotted in the double-logarithmic mode, both the positive and negative bias regions, as shown in Figure 8a,b, respectively. The conduction mechanism being responsible for charge transport in the low-voltage region involves ohmic behavior (since n = 1), but it is different in the medium- and high-voltage regions for the device, where the conduction behavior can be well described by the space charge-limited current (SCLC) theory [31-36]. Ohmic conduction in LRS is assumed to be caused by the oxygen vacancies which probably provide shallow energy levels below the conduction band edge. The SCLC mechanism is generally observed when the electrode contacts are highly carrier injecting. Due to the formation of an interfacial ZrOy layer between Zr and CeOx films, the conduction mechanism in the device behaves according to the SCLC theory since the ZrOy layer is known to provide electron trapping sites and to control the conductivity by trapping and detrapping.


Forming-free bipolar resistive switching in nonstoichiometric ceria films.

Ismail M, Huang CY, Panda D, Hung CJ, Tsai TL, Jieng JH, Lin CA, Chand U, Rana AM, Ahmed E, Talib I, Nadeem MY, Tseng TY - Nanoscale Res Lett (2014)

I-V curves of the Zr/CeOx/Pt memory device are displayed in double-logarithmic scale. The linear fitting results in both ON state and OFF state: (a) positive-voltage region and (b) negative-voltage region. The corresponding slopes for different portions are also shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927661&req=5

Figure 8: I-V curves of the Zr/CeOx/Pt memory device are displayed in double-logarithmic scale. The linear fitting results in both ON state and OFF state: (a) positive-voltage region and (b) negative-voltage region. The corresponding slopes for different portions are also shown.
Mentions: In order to elucidate the conduction mechanisms of the device, the I-V curve is plotted in the double-logarithmic mode, both the positive and negative bias regions, as shown in Figure 8a,b, respectively. The conduction mechanism being responsible for charge transport in the low-voltage region involves ohmic behavior (since n = 1), but it is different in the medium- and high-voltage regions for the device, where the conduction behavior can be well described by the space charge-limited current (SCLC) theory [31-36]. Ohmic conduction in LRS is assumed to be caused by the oxygen vacancies which probably provide shallow energy levels below the conduction band edge. The SCLC mechanism is generally observed when the electrode contacts are highly carrier injecting. Due to the formation of an interfacial ZrOy layer between Zr and CeOx films, the conduction mechanism in the device behaves according to the SCLC theory since the ZrOy layer is known to provide electron trapping sites and to control the conductivity by trapping and detrapping.

Bottom Line: X-ray photoelectron spectroscopy study confirmed the presence of oxygen vacancies in both of the said regions.In the low-resistance ON state, the electrical conduction was found to be of ohmic nature, while the high-resistance OFF state was governed by trap-controlled space charge-limited mechanism.The stable resistive switching behavior and long retention times with an acceptable resistance ratio enable the device for its application in future nonvolatile resistive random access memory (RRAM).

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu 30010, Taiwan. tseng@cc.nctu.edu.tw.

ABSTRACT
The mechanism of forming-free bipolar resistive switching in a Zr/CeOx/Pt device was investigated. High-resolution transmission electron microscopy and energy-dispersive spectroscopy analysis indicated the formation of a ZrOy layer at the Zr/CeOx interface. X-ray diffraction studies of CeOx films revealed that they consist of nano-polycrystals embedded in a disordered lattice. The observed resistive switching was suggested to be linked with the formation and rupture of conductive filaments constituted by oxygen vacancies in the CeOx film and in the nonstoichiometric ZrOy interfacial layer. X-ray photoelectron spectroscopy study confirmed the presence of oxygen vacancies in both of the said regions. In the low-resistance ON state, the electrical conduction was found to be of ohmic nature, while the high-resistance OFF state was governed by trap-controlled space charge-limited mechanism. The stable resistive switching behavior and long retention times with an acceptable resistance ratio enable the device for its application in future nonvolatile resistive random access memory (RRAM).

No MeSH data available.


Related in: MedlinePlus