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Experimental Observation of Non-Volatile Charge Injection and Molecular Redox in Fullerenes C60 and C70 in an EEPROM-Type Device

Published online by Cambridge University Press:  01 February 2011

Udayan Ganguly
Affiliation:
Department of Materials Science and Engineering
Chungho Lee
Affiliation:
School of Electrical and Computer Engineering, Cornell University
Edwin C. Kan
Affiliation:
School of Electrical and Computer Engineering, Cornell University
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Abstract

Molecular interface with CMOS is an area indispensable to the enhancement of our understanding of the nano-scale world. We report the integration of fullerenes in CMOS gate stack and demonstrate a functional molecular interface by effecting molecular redox operations through non-volatile charge injection in an EEPROM-type device. The gate stack of the MOS capacitor consists of a tunneling thermal oxide. A sub-monolayer of fullerenes is deposited. Then the control oxide is deposited and finally the gate metal is patterned. Charge injection occurs at a specific potential of the fullerene molecules with respect to the conduction band of Si at the Si/SiO2 interface, independent of the concentration of the fullerene sub-monolayer. This strongly indicates molecular redox in solid state that is electrostatically controllable. Such molecular interfaces can be used to enhance the spatial sensitivity of chemical sensors like the CνMOS to be able to interface with macromolecular systems.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

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[5] There is a numerical discrepancy in the VF extraction with [3]. In our previous work [3], tunneling oxide thickness was measured in as 2–3 nm using 3 wavelength Rudolph Ellipsometer. The calculations were done using 2 nm tunnel oxide. Currently, better measurement using a spectroscopic ellipsometer shows that the oxide is 2.7 nm for the C60 experiments and 2.4 nm for the C70 experiments. This does not disturb our arguments that the injections occur into molecular levels of the fullerenes since the different tunneling oxide thickness just scales VF to a different value. This VF is same for all devices with the same fullerene when the same tunnel oxide thickness is used for VF extraction.Google Scholar