High-k Dielectric Nanocrystals


Times Beacon Record Article

Prof. Dickerson has been featured in a recent article, entitled BNL's James Dickerson: facilitating nanotechnology.  Check it out!

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Prof. Dickerson just recently Guest Edited the Journal of the Electrochemical Society’s Focus Issue on Electrophoretic Deposition (http://jes.ecsdl.org/content/162/11.toc).  This collection of articles on EPD features many of the cutting-edge trends in the field.

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Monolayer Ticker

A new article on nanoparticle monolayer formation, led by Alex Krejci, was published in ACS Applied Materials and Interfaces.

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Shalom and Jyotishka have had their manuscript on electrochemical separation of carbon nanotube films published by the Journal of the Electrochemical Society. Congratulations Jyotishka and Shalom!

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Our article on iron oxide nanoparticle monolayer formation by electrophoretic deposition was published by ACS Materials and Interfaces.

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Hardcover versions of Electrophoretic Deposition of Nanomaterials can be accessed via the 'Read Article' link below.

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The Spring 2012 MRS Conference was a great success.  Prof. Dickerson presented an Invited Talk on our Rare Earth Nanoparticles.  He also will be the Editor of the YY:Rare-Earth-Materials Section of the MRS Conference Proceedings.

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Article on graphene oxide films published in ACS Nano.

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4

Weidong He has finished his PhD with us. Congratulations, Weidong, and best of luck at Pacific Northwest National Laboratory!

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Dr. Suseela Somarajan successfully defends her PhD dissertation. Congratulations Suseela!

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Prof. Dickerson is awarded a National Science Foundation CAREER Award!

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Synopsis:

Gadolinium oxide (Gd2O3) is of research interest as a replacement material for silicon dioxide in silicon-based electronics because of its high dielectric constant (κ = 14).  Recently, we have discovered that films comprised of nanocrystalline Gd2O3 revealed intriguing charge storage characteristics, particularly when arranged as the oxide layer of a metal–oxide–semiconductor structure.  We have fabricated such nanocrystalline films via electrophoretic deposition and have shown that our findings could lead to viable alternatives to silicon-based systems for a variety of electronics applications, such as non-volatile memory.

Major Achievements:

All nanocrystal films can be employed as charge storage, dielectric materials.  A portion of this research is the subject of a patent application.

Detailed Discussion:

Gd2O3 in its bulk crystalline and amorphous phases has been of research interest as a replacement material for silicon dioxide in transistors and other electronic devices because of its relatively high dielectric constant ( vs. ).  Discovery of a high-κ dielectric material, nanocrystalline or otherwise, could make possible a number of technological advances regarding computing (energy efficiency, processing speed) telecommunications (bandwidth, speed), among others.  Recently, dielectric studies of amorphous Gd2O3 films, embedded with Gd2O3 NCs, revealed intriguing charge storage characteristics of the NCs.  Similarly, metallic NCs (gold and cobalt) and semiconducting NCs (silicon) have exhibited charge-storage characteristics when they were embedded in the gate oxide of a metal–oxide–semiconductor (MOS) structure for non-volatile memory applications.

This motivated us to explore whether films composed entirely of colloidal Gd2O3 nanocrystals could possess similar charge-storage capabilities.  Charge storage in NC films arises from unpassivated surface states that can arise due to the detachment of some fraction of the surfactant molecules form the NCs’ surface during sample preparation.  Thus, we employed EPD to produce films consisting only of colloidal Gd2O3 NCs to be used as the gate oxide layer in MOS architecture.  We focused on capacitance-voltage (C-V) measurements of these MOS structures to characterize both the charge-storage and the dielectric properties of these films (See the Figure).

Reference Articles:

a. S.V. Mahajan and J.H. Dickerson, Dielectric properties of colloidal Gd2O3 nanocrystal films fabricated via electrophoretic deposition, Applied Physics Letters 96, 113105, 2010.
b. S.V. Mahajan and J.H. Dickerson, Understanding the growth of Eu2O3 nanocrystal films made via electrophoretic deposition, Nanotechnology 21, 145704, 2010.


© Copyright 2017 by James H. Dickerson II.

James H. Dickerson

Brown University