Probing the optoelectronics of graphene nanoribbons on the atomic scale withterahertz scanning tunneling microscopy
Abstract
TITLE: Probing the optoelectronics of graphene nanoribbons on the atomic scale with terahertz scanning tunneling microscopyObjective:To explore the optoelectronic properties of graphene nanoribbons (GNRs) on the femtosecond time-scale and Angstrom spatial resolution by combining state-selective terahertz lightwave-driven scanning tunneling microscopy with ultrafast optical excitation at tunable pump frequency and pulse duration. Approach:PI and his team will employ a state-of-theart low-temperature (4 K) ultrahigh vacuum terahertz scanning tunneling microscope capable of detecting less than one rectified tunnel electron per terahertz pulse. The associated laser system will be equipped with an optical parametric amplifier to enable broad tuning of the optical excitation wavelength and pulse duration. The optical pulseswill resonantly excite interband transitions in tailored GNRs globally. To locallycharacterize the resulting transient electron population and the dynamic local density of states in the 100 femtosecond to 100 picosecond time window after excitation within a single GNR, the team will develop a novel time-resolved analog of scanning tunneling spectroscopy. SOW:Year 1:Establish THz-STM setup and test rectification of model GNRs; Write algorithm for extracting i(v) from THz measurements of unexcited GNRs; Test protocols foron-surface synthesis of model GNRs with spacer layers. Year 2:Incorporate optical pumping into THz- STM setup and test ultrafast optoelectronics of model GNRs; Extend extraction algorithm to i(v,t)for time-resolved THz-STS; Synthesize alternate GNRs and testspacer layer growth procedures further.Year 3:Explore ultrafast optoelectronics of functionalized GNRs with THz-STM and THz-STS; Model i(v,t) extracted from time-resolved THz-STS data.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 23, 2019
- Source ID
- N000141912051
Entities
People
- Tyler L. Cocker
Organizations
- Michigan State University
- Office of Naval Research
- United States Navy