Academic literature on the topic '2D material technology'

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, May, 2020<br>Cataloged from student-submitted PDF of thesis.<br>Includes bibliographical references (pages 198-209).<br>Over the past 50 years, electronics has truly revolutionized our lives. Today, many everyday objects rely on electronic circuitry from gadgets such as wireless earbuds, smartphones and laptops to larger devices like household appliances and cars. However, the size range of electronic devices is still rather limited from the millimeter to meter scale. Being able to extend the reach of electronics from the size of a red blood cell to a skyscraper would enable new applications in many areas including energy production, entertainment, environmental sensing, and healthcare. 2D-materials, a new class of atomically thin materials with a variety of electric properties, are promising for such electronic systems with extreme dimension due to their flexibility and ease of integration. On the macroscopic side, electronics produced on thin films by roll-to-roll fabrication has great potential due to its high throughput and low production cost. Towards this end, this thesis explores the transfer of 2D-materials onto flexible EVA/PET substrates with hot roll lamination and electrochemical delamination using a custom designed roll-to-roll setup. The transfer process is characterized in detail and the lamination of multiple 2D material layers is demonstrated. As exemplary large-scale electronics application, a flexible solar cell with graphene transparent electrode is discussed. On the microscopic side, this thesis presents a 60x60 [mu]m² microsystem platform called synthetic cells or SynCells. This platform offers a variety of building blocks such as chemical sensors and transistors based on molybdenum disulfide, passive germanium timers, iron magnets for actuation, as well as gallium nitride LEDs and solar cells for communication and energy harvesting. Several system-level applications of SynCells are explored such as sensing in a microfluidic channel or spray-coating SynCells on arbitrary surfaces.<br>by Marek Hempel.<br>Ph. D.<br>Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

Questa tesi analizza la possibile implementazione di due tipologie di dispositivi elettronici con funzionalità innovative: dispositivi per la computazione quantistica e transistors a film sottile. Negli ultimi decenni l’industria dei semiconduttori ha portato alla realizzazione di circuiti integrati con milioni di transistors e performance sempre migliori a costi contenuti. Tuttavia, questo processo di miniaturizzazione è giunto a un punto tale che i dispositivi elettronici sono ora composti da pochissimi atomi e ridurne ulteriormente le dimensioni sta diventando sempre più difficile. L’International Technology Roadmap of Semiconductors (ITRS) suggerisce due vie alternative per migliorare le caratteristiche dei dispositivi a partire dalla Front-End-Of-Line. La prima si avvale di nuovi dispositivi sulla base di architetture innovative o dell’utilizzo di diverse variabili di stato (Emerging Research Devices), mentre la seconda punta all’utilizzo di nuovi materiali (Emerging Research Materials). Questa tesi esamina due possibili candidati in questa ottica: i dispositivi per la computazione quantistica su architettura Complementary Metal-Oxide-Semiconductor (CMOS) e i transistors a film sottile basati su un semiconduttore bidimensionale come il MoS2. Da un lato, l’integrazione della computazione quantistica su Si sfrutterebbe il background tecnologico dell’industria dei semiconduttori per implementare su larga scala un nuovo protocollo di computazione dotato di un potenziale enorme e ancora inesplorato. D’altra parte il di-solfuro di molibdeno (MoS2) è intrinsecamente scalabile, in quanto può essere esfoliato fino allo spessore di un singolo strato atomico. Per questo motivo potrebbe essere un semiconduttore ideale per dispositivi elettronici ultrascalati, così come per applicazioni nella sensoristica, nell’optoelettronica e nell’elettronica flessibile. Questo lavoro mostra l’attività svolta al Laboratorio MDM-IMM-CNR nell’ambito del corso di dottorato in Nanostrutture e Nanotecnologie all’Università di Milano Bicocca. Lo sviluppo e l’utilizzo di processi di fabbricazione della nanoelettronica, in particolare la litografia a fascio elettronico (EBL), sono stati parte integrante dell’attività sperimentale dedicata alla realizzazione di dispositivi CMOS-compatibili per la computazione quantistica e per l’integrazione di film sottili di MoS2 in strutture Metal-Oxide-Semiconductor Field-Effect-Transistor (MOS FET). I necessari passi di processo sono stati adeguatamente calibrati e ottimizzati in modo da ottenere dispositivi quantistici basati su Quantum Dots (QD) con dimensioni caratteristiche inferiori a 50 nm. Tali dispositivi sono stati sviluppati con tecnologia Silicon-On-Insulator (SOI), mantenendo così la compatibilità con lo standard della tecnologia CMOS. Dispositivi a singolo donore e con QD di silicio sono stati poi caratterizzati elettricamente a temperature criogeniche (fino a 300 mK). Impulsando i potenziali di gate in modo controllato, è stato possibile studiare fenomeni di tunneling di singoli elettroni su un donore in alti campi magnetici (8T). In modo analogo è stato dimostrato il controllo dello stato di carica di QDs di Si. In particolare, si è osservato l’insorgere di rumore telegrafico associato al movimento di un singolo elettrone tra due QDs. Infine è stato condotto uno studio di fattibilità per l’integrazione su larga scala di un’architettura di computazione quantistica (il cosiddetto hybrid spin qubit) basata su doppi QDs di Si. Sul secondo fronte sono stati realizzati dei MOS FETs a film sottile basati su frammenti di MoS2, ottenuti per esfoliazione meccanica e contattati elettricamente tramite litografia EBL. Tali transistors sono poi stati caratterizzati elettricamente, con particolare attenzione alle proprietà di trasporto di carica e alla spettroscopia delle trappole all’interfaccia con l’ossido.<br>This work of thesis explores two emerging research device concepts as possible platforms for novel integrated circuits with unconventional functionalities. Nowadays integrated circuits with advanced performances are available at affordable costs, thanks to the progressive miniaturization of electronic components in the last decades. However, bare geometrical scaling is no more a practical way to improve the device performances and alternative strategies must be considered to achieve an equivalent scaling of the functionalities. The introduction of conceptually new devices and paradigms of information processing (Emerging Research Devices) or new materials with unconventional properties (Emerging Research Materials) are viable approaches, as indicated by the International Technology Roadmap of Semiconductors (ITRS), to enhance the functionalities of integrated circuits at the Front-End-Of-Line. The two options investigated to this respect are silicon devices for quantum computation based on a classical Complementary Metal-Oxide-Semiconductor (CMOS) platform and standard Metal-Oxide-Semiconductor Field-Effect-Transistors (MOSFETs) based on MoS2 thin film. In particular, the integration of Quantum Information Processing (QIP) in Si would take advantage of Si-based technology to introduce a completely new paradigm of information processing that has the potential to outperform classical computers in some computational tasks, like prime number factoring and the search in a big database. MoS2, conversely, can be exfoliated up to the single layer thickness. Such intrinsic and extreme scalability makes this material suitable for end-of-roadmap ultrascaled electronic devices as well as for other applications in the fields of sensors, optoelectronics and flexible electronics. This work reports on the experimental activity carried out at Laboratory MDM-IMM-CNR in the framework of the PhD school on Nanostructures and Nanotechnology at Università di Milano Bicocca. Electron Beam Lithography (EBL) and mainstream clean-room processing techniques have been intensively utilized to fabricate CMOS devices for QIP on the one hand and to integrate mechanically exfoliated MoS2 flakes in a conventional FET structure on the other hand. After a careful calibration and optimization of the process parameters, several different Quantum Dot (QD) configurations were designed and fully realized, achieving critical dimensions under 50 nm. Such device architectures were developed on a Silicon-On-Insulator (SOI) platform, in order to eventually access a straightforward integration into the CMOS mainstream technology. Si-QDs and donor-based devices have been then tested by electrical characterization techniques at cryogenic temperatures down to 300 mK. In detail, single electron tunneling events on a donor atom have been controlled by pulsed-gate techniques in high magnetic fields up to 8T, providing a preliminary characterization for the initialization procedure of donor qubits. The control of the charge states of Si-QDs have been also demonstrated by means of stability diagrams as well as the analysis of random telegraph noise arising from single electron tunneling between two QDs. Finally, a feasibility study for the large scale integration of quantum information processing was done based on a double QD hybrid qubit architecture. On the other side, MoS2 thin film transistors have been made by mechanical exfoliation of crystalline MoS2 and electrodes definition by EBL. Electrical characterization was performed on such devices, with a particular focus on the electrical transport in a FET device and on the spectroscopy of interface traps, that turns out to be a limiting factor for the logic operation.