Hao-Li Zhang

Hybrid silicon-organic nanoparticle memory device

We demonstrate a nonvolatile electrically erasable programmable read-only memory device using gold nanoparticles as charge storage elements deposited at room temperature by chemical processing. The nanoparticles are deposited over a thermal silicon dioxide layer that insulates them from the device silicon channel. An organic insulator deposited by the Langmuir–Blodget technique at room temperature separates the aluminum gate electrode from the nanoparticles. The device exhibits significant threshold voltage shifts after application of low-voltage pulses (⩽±6 V) to the gate and has nonvolatile retention time characteristics.

Surface functionalisation for the self-assembly of nanoparticle/polymer multilayer films

The use of organosilanes as surface functionalising materials has been investigated as a precursor to the adsorption of ligand stabilised gold nanoparticles and the build-up of nanoparticle/polymer multilayer films. The purpose of surface functionalisation here is to produce a uniform surface with the maximum positive charge possible to enable the efficient adsorption of negatively charged gold nanoparticles. It is generally acknowledged that the characteristics of the first layer are important in determining the quality of the subsequent multilayer film and hence careful attention has been paid to its optimisation. Three aminosilanes have been investigated together with various methods for their deposition. The degree of nanoparticle adsorption in the resulting films was characterised using atomic force microscopy and X-ray photoelectron spectroscopy. The surface potential of the aminosilane films was also measured to provide information regarding the surface charge density. Our results show a strong correlation between the nanoparticle density and the initial surface charge density. Films of 3-aminopropyltriethoxysilane adsorbed from toluene yielded the highest level of nanoparticle adsorption.

Synthesis of novel biotin anchors

Abstract Details are reported of the synthesis of biotinylated thiol and cholesteryl derivatives. The biotin derivative has been used to form multilayer films on gold through interaction with streptavidin.

A multi-stack insulator silicon-organic memory device with gold nanoparticles

We demonstrate a memory device, using gold nanoparticles as charge storage elements deposited at room temperature by chemical processing. The nanoparticles are deposited over a thin thermal silicon dioxide layer that insulates them from the device silicon channel. An organic insulator deposited by the Langmuir-Blodget technique at room temperature separates the aluminium gate electrode from the nanoparticles. The device exhibits significant threshold voltage shifts after application of low voltage pulses (</spl plusmn/7 V) to the gate and has non-volatile retention time characteristics.