Atomically precise single Graphene Nanoribbon transistor

This dissertation addresses the challenges in fabricating single graphene nanoribbon (GNR) transistors, particularly the difficulty in forming reliable and reproducible metal contacts. A novel low-voltage, direct-write scanning tunneling microscopy (STM) technique is introduced to pattern sub-5 nm metallic hafnium diboride (HfB2) contact pads directly onto individual GNRs in an ultrahigh vacuum environment. Scanning tunneling spectroscopy (STS) verifies the metallic and semiconducting natures of the HfB2 and GNRs, respectively, demonstrating that the STM process does not damage the GNRs. The deposition of HfB2 induces band-bending in the GNRs, forming local p-n junctions, and the degree of band-bending can be controlled by varying the metal work functions, eliminating the need for complex chemical doping. This contact engineering method simplifies the fabrication process for high-performance single GNR transistors. Additionally, the dissertation explores the fabrication of larger electrodes for transport measurements and the challenges associated with electrode instability and thermal damage during the cleaning process. The potential applications of STM-EBID for fabricating 3D nanostructures, including mechanical resonators, switches, and single-photon detectors, are also discussed. This work marks a significant advancement in GNR-based nanoelectronics, providing a reliable approach for precise metal contacts and furthering the integration of GNRs into functional electronic devices.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Huang, Pin-Chiao

Contributors dc:contributor

• Lyding, Joseph W
• Rakheja, Shaloo
• Girolami, Gregory S
• Dragic, Peter D
• Sinitskii, Alexander

• silicon
• scanning tunneling microscopy
• surface cleaning
• atomically flat
• graphene nanoribbon

Statement dc:rights

• Copyright 2025 Pin-Chiao Huang

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129664

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129664