Quantum-transport analysis of transistors based on nanoribbons of novel 2D materials

doctoral thesis

• Title (croatian): Kvantnotransportna analiza tranzistora temeljenih na nanovrpcama novih 2D materijala
• Author: Mislav Matić
• Mentor: Mirko Poljak (mentor)
• Committee member: Marko Koričić (predsjednik povjerenstva)
• Committee member: Tomislav Marković (član povjerenstva)
• Committee member: Ivor Lončarić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Electronics, Microelectronics, Computer and Intelligent Systems); Zagreb
• Defense date and country: 2024-10-25, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

The development and optimization of future logic electron devices strongly relies on novel materials and device architectures. One of the most promising research paths is presented by 2D materials patterned into quasi-one-dimensional (1D) nanostructures known as nanoribbons. The aim of this dissertation was to develop an ab initio quantum transport method to assess the potential of quasi-1D materials for future extremely-scaled field-effect transistors (FETs). The investigated materials include armchair (AC) and zigzag (ZZ) nanoribbons of MX2-enes (MX2NRs) with M = {Hf, Zr} and X = {S, Se}, AC and ZZ nanoribbons of monolayer germanium sulfide (GeSNRs), as well as nanoribbons of monolayer molybdenum disulfide (MoS2NRs). The ab initio quantum transport study is performed using density functional theory (DFT) and maximally localized Wannier functions (MLWFs) to obtain the electronic structure and device Hamiltonians. The obtained atomistic Hamiltonians are coupled with the non-equilibrium Green’s function (NEGF) formalism-based numerical solver for quantum transport simulations of FETs. The thesis investigated the performance of nanoribbon FETs in detail and supported the findings by examining the electronic and transport properties of these nanostructures. The results showed that nanostructured Hf- and Zr-based MX2-enes and GeS present a promising platform for future ultra-scaled high-performance logic devices.

Abstract (croatian)

Razvoj i optimizacija logičkih elektroničkih elemenata oslanja se na nove materijale i arhitekture elemenata. Jedan od najperspektivnijih pravaca istraživanja novih elemenata je primjena 2D materijala oblikovanih u kvazi-jednodimenzionalne (kvazi-1D) nanostrukture, nazvane nanovrpcama. Cilj ove doktorske disertacije bio je razviti metodu temeljenu na ab initio kvantnotransportnom izračunu kako bi se istražio potencijal kvazi-1D materijala za ekstremno skalirane tranzistore s efektom polja (engl. field-effect transistor, FET). Materijali čiji se potencijal istraživao uključuju armchair (AC) i zigzag (ZZ) nanovrpce MX2-ena (MX2NR) s M = {Hf, Zr} i X = {S, Se}, AC i ZZ nanovrpce germanij-sulfida (GeSNR), kao i nanovrpce molibden-disulfida (MoS2NR). Ab initio kvantnotransportne simulacije izvedene su korištenjem teorije funkcionala gustoće (DFT) i maksimalno lokaliziranih Wannierovih funkcija (MLWF) za dobivanje elektronske strukture i hamiltonijana nanovrpci. Dobiveni hamiltonijani povezani su sa numeričkim simulatorom kvantnog transporta koji se temelji na formalizmu Greenove funkcije izvan ravnoteže (NEGF) za simulaciju FET-ova. U disertaciji su detaljno istražene performanse FET-ova temeljenih na nanovrpcama, a dobiveni rezultati su objašnjeni analizom elektronskih i transportnih svojstva istraživanih nanostruktura. Rezultati istraživanja pokazuju da su nanostrukturirani GeS te MX2-eni temeljeni na hafniju i cirkoniju materijali s obećavajućim svojstvima za buduće ultra-skalirane logičke elemente visokih performansi.

• Keywords: two-dimensional (2D) materials; one-dimensional (1D); quasi-1D; nanoribbon; density functional theory (DFT); maximally localized Wannier functions (MLWFs); quantum transport; non-equilibrium Green’s function (NEGF) formalism; ballistic transport; top-of-the-barrier (TOB) model
• Keywords (croatian): dvodimenzionalni (2D) materijali; jednodimenzionalno (1D); kvazi-1D; nanovrpca; teorija funkcionala gustoće (DFT); maksimalno lokalizirane Wannierove funkcije (MLWF); kvantni transport; formalizam Greenovih funkcija izvan ravnoteže (NEGF); balistički transport; model vrha barijere (TOB)
• Language: english
• URN:NBN: urn:nbn:hr:168:072309
• Promotion: 2025
• Study programme: Title: Doctoral study programme "Electrical Engineering and Computing"; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, po-dručje tehničkih znanosti (doktor/doktorica znanosti, po-dručje tehničkih znanosti)
• Type of resource: Text
• Extent: 119 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-01-29 12:39:35