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A Si based technology route to chemical vapor deposition of large area graphene
No full textThe era of two-dimensional materials has begun with graphene. It is the first artificially-isolated single-atom-thick material, which is also an exceptional example of its kind. With its extraordinary physical and chemical properties, it has become hugely popular among scientists and technologists isn a timeframe of less than a decade. When first isolated, graphene has been a subject of fundamental research by condensed matter physicists. Later, the possibility to exploit graphene's applicability have brought research toward methods for large scale production. One leading technique to obtain graphene is by its synthesis on sacrificial substrates by Chemical Vapor Deposition (CVD). Thus, a great deal of interest in research and development of graphene has risen all over the world. This thesis work has been conducted at INRiM (Istituto Nazionale di Ricerca Metrologica) and has addressed the synthesis of graphene by CVD on copper, which has become the most popular catalyst for graphene growth. The entire CVD process, performed on both Cu thin films and foils, is here presented as well as transfer methods are discussed. Growth of graphene is discussed also in terms of direct deposition onto insulating substrates, and preliminary results are reported. Finally, a first approach on electrical characterization of graphene grown on Cu foils is described. Although many aspect of graphene growth have been developed, the main work has been done on the growth of graphene on Cu thin films investigating the possibility of lowering the film thickness. This goal was in competition with dewetting phenomena: thin films energy minimization at high temperature, indeed, let the film to dewet forming holes and eventually islands. In chapter 3 is reported an analysis on Cu thin films dewetting, results of chapter 3 are used in chapter 4 where CVD on such thin films is reported. Chapter 5 deals with transferring methods of graphene, alongside of the "standard" method a new technique is proposed. In Chapter 6 the direct deposition onto insulating substrates is investigated via a method where Cu is used as a remote catalyzer. In the last chapter the electrical characterization of graphene is approached with the aim of demonstrating the feasibility of performing also this characterization procedure in INRiM lab
Temperature study of CVD graphene on Cu thin films: competition between C catalysis and Cu dewetting
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Cryogenic setup for electron counting experiments
No full textThis technical report describes the electrical and mechanical configuration of a system devoted to the mise en pratique of the DC electrical current in the range 100 fA - 100 pA. A commercial dilution refrigerator (Leiden Cryogenics B.V. MicroKelvin-50), installed in the Cryogenic Laboratory (b302b @ INRiM), represents the starting point of the measurement setup. The instrument allows the achievement of a base temperature near 30 mK, this latter being necessary for the implementation of a single-electron-transistors- device-based current source. The entire measurement set up has been designed to fulfill the strict low-noise ambient requirements reaching a state-of-the-art configuration in the field of quantum metrology of low currents. The problem of the transport of the electrical signals from room temperature electronics (isolated voltage sources, low-noise current amplifier..) to the devices located in the coldest region of the refrigerator has been faced with a multi-stage modular approach. In this view several custom components have been designed and developed, keeping in mind the metrological scope of the whole experimen
Laser-induced etching of few-layer graphene synthesized by Rapid-Chemical Vapour Deposition on Cu thin films
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