Towards Coherent Control of Current Injection in Graphene via Quantum Interference in Charge Carrier Excitations

Abstract

This thesis investigates the coherent control of photocurrent generation in graphene through interband transitions, utilizing femtosecond laser pulses at room temperature. We developed and characterized graphene field e!ect transistors (GFETs) using three distinct fabrication methods, culminating in a fully PCB-mounted device for optoelectronic measurements. Physical and chemical characterization of the devices, including AFM, voltage-current measurements, and X-ray surface analysis, confirmed the presence of single layer graphene with an average sheet resistance of 4kOhms. Using a custom-built two-colored Michelson interferometer, we demonstrated its capability to perform interferometric measurements of E^2ω E2ω fields, employing harmonically related beams at ωω = 808nm and ω2ω = 404nm. While the setup successfully detected voltage signals of approximately 600µV from the graphene devices, the targeted current injection phenomenon was not observed. These results provide valuable insights into the experimental challenges and requirements for achieving coherent control of current injection in graphene-based devices.