SSL Seminar Series 2002 No.7

Combined talks (two speakers)

Date: November 22, 2002
Time: 5:00-6:00pm
Physics Conference Room (Blk S13 M01-15)

Speaker I: Mr. Md. Abdul Kader Zilani
Title: STM studies of large molecules on surfaces for molecular electronic applications

Molecular devices with novel quantum properties are potentially the building block of future nanoscale electronic devices. In this work, we will study the electronic properties of self-assembled organic molecules, as well as variation of electronic properties under the influence of a particular substrate. In addition, we will investigate the molecule-induced surface reconstructions, and study the controlled-assembly and manipulation of organic molecules on different substrates to build specific nanostructures. Fullerenes represent a unique structure of cage molecules with a wide range of sizes, shapes and molecular weights. C60 makes strong bond with Si surfaces due to its large number of dangling bonds compared with GaAs and other surfaces. Currently we are studying the interaction of C60 with passivated-Si surfaces and on the effect of adsorbates to modify C60 layers. The study of self-assembly on passivated surfaces and also passivation effect of C60 monolayer and multilayer are important in term of molecular ordering, bonding and conductivity of C60 films. Next part of our research consists of controlled fabrication of nanostructure and study of electrical properties of organic molecules such as (C60 and C70) buckyballs. We will grow fullerene-based nanostructures on Si surface using oxygen as a mask. We want to grow nano-wire of few molecular widths within the window of etched oxidized Si surface.

Speaker II: Mr. Mayandi Jeyanthinath
Title: STM Studies of growth and Ordering in Ge/Si(100) Multi-layer Quantum Dots

Growth and ordering of multi-layer Quantum dots (QDs) is an important field, in the development of nano and optoelectronic devices, due to their novel properties. The growth conditions of ordered and uniform size multi-layer QDs have to be investigated. To study the growth conditions, we will use an in situ ultrahigh vacuum (UHV) scanning tunneling microscope (STM). Here we present the key problems and explain how we will carry out the study of the atomic processes of the multi-layer QDs growth, to reveal the roles of the spacer layers, surface reconstruction, kinetic roughening, intermixing, temperature and segregation. Based on these studies, we can find an optimal growth condition for growing organized multi-layer QDs.