Exploring molecule metal and molecule topological insulator interface at atomic scale

Abstract

The silicon revolution in 1970s and 1980s made technology accessible to everyonein the form of personal computers It also propelled the information revolutionthat connected the world with rapid advances in internet and wireless communication also known today as the internet of things IoT A natural progression in thiscourse was the miniaturization of devices aiming for high speed and low power consumptionin all designs In 1965 Gordon Moore the co founder of Intel said thatthe number of transistors would double every 18 months an observation referredto as the 8220 Moore 8217 s law 8221 The fabrication and miniaturization in silicon devices hasreached the spatial limits calling out for paradigm shifts in designing new technologies One such candidate on this frontier has been organic molecules Using themfor designing electronic devices a pathbreaking idea first proposed by Aviram andRatner in 1974 sowed the seeds of 8216 molecular electronics 8217 Since then there havebeen efforts worldwide to harness the electronic properties of molecules towards thisgoal The advantage of using molecules is their stability small size and extensive structuraland electronic tunability for desired functionalities Self assembled molecules SAM supported by a substrate are an excellent platform to explore device functionalitiesin molecules However before converging upon a realistic application fundamental questions like how do single molecules behave how do their energylevels align with the substrate what happens at the interface how do molecules selfassemble how does electron transport occur between the molecules and substrate and so on need to be addressed This thesis has attempted to answer some of thesequestions using Scanning Tunneling Microscopy STM and Scanning TunnelingSpectroscopy STS at Low Temperature LT of 77 K and in Ultra High Vacuum UHV The spatial high reso newline newline