U ~ Coulomb Band gap

Mott Insulator

1.6 1.5 1.4 1.3 1.2 1.1

RD

2

Inter-particle couplingStrong

couplingWeakcoupling

Metal-Insulator Transition

Quantum Dot Quantum Dot Designed SolidsDesigned Solids

Heath group contactsKris Beverly: kristen@chem.ucla.eduParul Chaudhari: Kristen Koch: Also: Raphy Levine, Francoise Remacle, and Jose SampaioFunding: CULAR; DOE

150 300

e17

e21

e25

Res

ista

nce

Temperature80

Ea from slope

280

320

360

acti

vati

on

en

erg

y (

K )

140 210 280area (cm2)

-1.0 0 1.0I(

nA

)

Volts

ND

OS

Single e phenomena

Cooperative phenomenaIn this project, we are trying to

develop quantum dot solids as model systems for understanding the elec-tronic properties of low-dimensional solids. At top left is a TEM image of a single monolayer of 7 nm diameter, organically passivated silver quantum dots, and this is our model system for study. At top right is a description of how the electronic properties of this superlattice vary as the interparticle separation distance is decreased (as quantum exchange coupling is turned on). When the particles are well isolated, the system is a Mott insulator, and exhibits single electron charging characteristics. When the particles are sufficiently close together, the system passes from an insulator to a metal. Then, as measured by DC transport, temperature dependence of the conductivity causes localization phenomena, which can be then quantified. The various curves at the bottom left reflect the temperature-dependent DC transport of such a superlattice as a function of interparticle separation distance.

A = 0 0 1 1B = 0 1 0 1

50

60

70

Cu

rren

t (1

0-9 A

mp

s)

A

B

A

B

SUM

Heath group contacts:Yi Luo: yiluo@chem.ucla.eduMichael Diehl: diehl@chem.ucla.eduErica DeIonno: deionno@chem.ucla.eduGreg Ho: gregho@chem.ucla.eduRob Beckman: beckman@chem.ucla.edu Nick Melosh: nmelosh@chem.ucla.eduEric Wong: ewwong@chem.ucla.edu Also: Fraser Stoddart Group &Hewlett Packard CorporationFunding: DARPA; SRC; NSF; ONR

Molecular ElectronicsMolecular Electronics

In this project we are trying to develop molecular electronics-based circuitry for computing applications. This project involves a broad range of scientific challenges, ranging from developing techniques for device scaling to a few nanometers length scale to computer architecture and molecular materials development. Clockwise, from top middle left: An artists version of a molecular switch tunnel junction using [2]catenane molecular switches. The central figure is a distorted micrograph of a 16-bit molecular memory circuit at device size of ~0.0025 microns 2. Right top center is data from a 16-bit molecular electronic random access memory circuit; far right is a [2]rotaxane molecular switch. Bottom right is a chemically assembled crossbar circuit using single-walled carbon nanotubes; bottom left is the truth table from an XOR molecular-based logic circuit; middle left is an artists depiction of a molecular electronic nanoscale crossbar.

Laser

Optical Layer

Nanofluidiclayer

SensorLayer

Sensors

Nanocell

Contact Pads

Valves

Micropumps

Waveguides

OpticalSplitter

Micromirror

Laser

Optical Layer

Nanofluidiclayer

SensorLayer

Sensors

Nanocell

Contact Pads

Valves

Micropumps

Waveguides

OpticalSplitter

Micromirror

Time (sec)0.00 0.05 0.10 0.15

Gat

ing

Cu

rren

t (A

mp

s)

0

2e-11

4e-11 VG = -10 mVVG = 100 mV

High throughput proteomics devices

Heath group contacts:Dr. Xin Yang xyang@chem.ucla.edu Dr. Hyeon Choi hchoi@chem.ucla.edu Rigo Pantoja rpantoja@chem.ucla.edu Ryan Riess riess@chem.ucla.eduAlso: Francisco Bezanilla (UCLA medical school) & Rich Sayaklly (UC Berkeley)Funding: W.M. Keck Foundation

In this collaboration with the UCLA medical school, and with the School of Engineering, we are trying to develop bio-device platforms for the combinatorial interrogation of transmembrane proteins in highly controlled environments. At top left is a ‘protein’ chip consisting of a lipid bilayer suspended across a pore micromachined into a silicon wafer. Voltage gating of the membrane reveals single channel protein gating characteristics. At top right is our targetted device: a library of cellular membranes in which we utilize fluidics, electronics, sensors, and optics to interrogate the proteins in a host of chemical and physical environments. At bottom left is a picture of a scanning non=linear optical microscope that we have constructed for this project. This microscope utilizes femtosecond laser exciation pulses, and collects the second harmonic generation signal and the two-photon fluorescence signal while retaining full polarization control over both input and output beams. The protein device is scanned in the x,y plane using large amplitude piezeoelectronic scanners.