Award Abstract #0102765
NER: Molecular Diode and Molecular Nonvolatile Memory

NSF Org:	CCF Division of Computer and Communication Foundations
Initial Amendment Date:	July 7, 2001
Latest Amendment Date:	July 7, 2001
Award Number:	0102765
Award Instrument:	Standard Grant
Program Manager:	S. Kamal Abdali CCF Division of Computer and Communication Foundations CSE Directorate for Computer & Information Science & Engineering
Start Date:	June 15, 2001
Expires:	October 31, 2001 (Estimated)
Awarded Amount to Date:	$99998
Investigator(s):	Jaewu Choi jchoi@ece.eng.wayne.edu (Principal Investigator)
Sponsor:	Louisiana State University & Agricultural and Mechanical College 202 Himes Hall Baton Rouge, LA 70803 225/578-2760
NSF Program(s):	SPECIAL PROJECTS - CCF
Field Application(s):
Program Reference Code(s):	HPCC, 9216, 9150, 1676
Program Element Code(s):	2878

ABSTRACT

PROPOSAL NO.: 0102765

PRINCIPAL INVESTIGATOR: Choi, Jaewu

INSTITUTION NAME: Louisiana State University & Agricultural and Mechanical College

TITLE: NER: Molecular Diode and Molecular Nonvolatile Memory

The proposed research program addresses the challenges and opportunities

available with molecular diode and molecular nonvolatile memory. The proposed

molecular diode and molecular nonvolatile memory can be achieved with carbon

nanotubes functionality and heterostructure of carbon nanotubes with a ferroelectric

linear polymer.

The carbon nanotube, itself, has many functional properties, such as quasi-one

dimensionality, metal-semiconductor, mechanical stiffness, capillarity, high aspect ratio,

large surface area, and chemical stability. In application of these carbon nanotubes to the

electronic devices, one serious obstacle is handling the chiarlity, which plays an

important role in determining the metallic-semiconducting behavior of the carbon

nanotubes. The proposed research program allows us to overcome these difficulties by

utilizing the carbon nanotubes as a backbone for a diode and a sensor for a nonvolatile

memory.

First of all, the proposed molecular diode consists of the differentially doped

single carbon nanotube. This is based on our own research work on the electronic

structure study of the modified carbon nanotubes by ion-bombardments, alkali metal

doping, and atomic and molecular gas adsorption. These recent studies show that the

density of states near Fermi level, work function, and band gap of the carbon nanotubes

can be tunable. Therefore, it does not require any junction of two carbon nanotubes with

different chirality to make a molecular diode, which has been suggested in a theoretical

calculation by growth of a single carbon nanotube with different chiraity. To make a

diode from a single carbon nanotube in this proposed research program, the half of the

tube will be doped with p-type acceptor (like oxygen or fluorine) and the other half will

be doped with n-type donors (alkali metals) using screening doping.

Secondly, the proposed molecular nonvolatile memory is a heterostructure of a

carbon nanotube and a ferroelectric linear polymer with a permanent dipole moment. The

carbon nanotube has been studied as a gas sensor and a gas-storage. Adsorption of gas on

carbon nanotube induces the conductivity change and band gap opening. In this proposed

carbon nanotube-ferroelectric polymer heterostructure, we are going to detect the

conductivity change of the carbon nanotube due to the electric dipole reorientation of the

ferrolectric polymer by applying the normal TTL (transistor-tansistor logic) voltage.

Therefore, the carbon nanotube-ferroelectric polymer heterostructure is the combination

of the sensor and information storage. The interface between the carbon nanotube and the

ferroelectric polymer, PVDF, of the proposed heterostructure systems is changed from

the hydrogen or fluorine rich to the hydrogen and fluorine mixture across the

conformational switching from all trans to gauch-trans-gauch bar with variation of

temperature or applied voltage (a gate voltage). This is the working principle of the

proposed molecular nonvolatile memory.

Through this proposed program on molecular diode and molecular nonvolatile

memory, graduate and undergraduate students will be involved and trained in the cutting-

edge research area (an emerging area of nanoscale science and technology, in special

molecular electronics) of science and technology with advanced synchrotron and

microfabrication facilities.

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