Shamjid, Could you be more specific about the type of device and materials that may be bistable? Or give a citation to a review article which talks about the type of devices you question?
Dear David Baldwin, I need to understand electrical bi-stability in organic bi-stable memory devices. All papers were treated the bi-stability along with I-V curve, but I failed to understand that. So I would like to get more idea about the bi-stability and a comparison between this type organic memory with in-organic memory...
Shamjid, OK. Thanks for those details. Do you have a paper or review article you could upload (PDF) or at least cite?
I am more familiar with inorganic resistive memory cells, such as Hewlett-Packard is developing using or based upon tantalum oxides. The I-V curve should be qualitatively similar to organic devices. What you see in some I-V curves is a zero-->positive-->zero-->negative-->zero voltage sweep, and the current that flows through the material at each voltage is measured. At small excursions of voltage, either positive or negative, Ohm's Law appears to be approximately obeyed, V/I = R, R being the resistance. R can be calculated from the slope of the I-V curve, in portions. At some extreme of voltage, either positive or negative, the material "switches" and the resistivity (and resistance R) changes. Thereafter, at small excursions of voltage, either positive or negative, Ohm's Law appears to be approximately obeyed, but with a new slope R. Is that fairly clear? The device engineer would use the high-voltage excursion as a "write" pulse, to set the memory cell to "0" or "1" resistance and would use the low voltage excursion pulses to "read" the state of the cell. Of course, if you plot the one I-V curve is which a switching event occurs, it would be a mess and not simple to interpret.
Does this answer something close to or part of what you were asking?
Shamid, If it is the I-V curve you may not understand, please look at Fig. 2 on page 148 (or page 4 of the arXiv manuscript) of:
Y.V. Pershin and M. Di Ventra, "Memory effects in complex materials and nanoscale systems", Adv. Phys. 60, 145-227 (2011).
The arXiv manuscript can be seen free at:
http://arxiv.org/pdf/1011.3053v1.pdf
Aside from the fact that these are not really "hysteresis" loops (maybe their derivatives are), see if you understand these. If not, ask more questions with reference to them. Then we have something specific we can talk about. Also, please do send the citation to the data you are actually asking about. Thanks!
Dear David,
I'm very grateful to you. I will contact you soon after reading the manuscript.
Dear David,
I want to know more about Electrical bistability of Organic memory. I had some papers related to this area, but I could not find more specific explanation about the I-V curve that tells about electrical bistability.
One of them I attached here to get you what I'm asking...
http://dx.doi.org/10.1063/1.1643547
The bistability is nothing but a two stable state at a single voltage, but I didn't understand what need of this two stable state at a single voltage.
In inorganic semiconductor system like (NOT,AND,OR gate), there is only one state either 1 or 0 at a single specific voltage.
Because of these I'm so confused about electrical bi-stability of organic memory devices...
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