Damage to Nanoscale Semiconductor Wires from Ultrashort Laser Pulses
Disciplines
Optics | Physics
Abstract (300 words maximum)
Cutting-edge optoelectronics increasingly use semiconductor nanowires. These nanowires are often made of semiconductor materials, which conduct electricity when excited, and can be millions of times thinner than a regular copper wire. Due to their structure, nanowires are extremely fragile, and they are vulnerable to incredibly short-duration—on the order of one femtosecond, or one millionth of a billionth of a second—laser pulses. However, the exact damage processes are not entirely understood for these novel quantum materials. In our research, we aim to understand when a nanowire exposed to intense fs laser light might fail and how to protect it from lasers of different colors and intensities. To this end, we simulate laser propagation through a GaAs nanowire and observe its post-exposure energy density and temperature. The propagation simulations numerically solve the Maxwell equations for the electric and magnetic fields in the region of the nanowire, and interface with laser-material interaction code that models the behavior of excited electrons in the semiconductor. These simulations are programmed and run on computer servers at KSU. Prior to each simulation, we vary the color and intensity of the laser pulse and observe how these might affect the damage process. We find that, at specific combinations of these parameters, the wire’s energy density and temperature exceed its melting point, which will cause irreversible damage to the structure. To provide an experimental test of our model, we also record the electric current generated by the process and any lingering electromagnetic radiation from the wire after the laser pulse’s departure.
Academic department under which the project should be listed
CSM - Physics
Primary Investigator (PI) Name
Jeremy Gulley
Damage to Nanoscale Semiconductor Wires from Ultrashort Laser Pulses
Cutting-edge optoelectronics increasingly use semiconductor nanowires. These nanowires are often made of semiconductor materials, which conduct electricity when excited, and can be millions of times thinner than a regular copper wire. Due to their structure, nanowires are extremely fragile, and they are vulnerable to incredibly short-duration—on the order of one femtosecond, or one millionth of a billionth of a second—laser pulses. However, the exact damage processes are not entirely understood for these novel quantum materials. In our research, we aim to understand when a nanowire exposed to intense fs laser light might fail and how to protect it from lasers of different colors and intensities. To this end, we simulate laser propagation through a GaAs nanowire and observe its post-exposure energy density and temperature. The propagation simulations numerically solve the Maxwell equations for the electric and magnetic fields in the region of the nanowire, and interface with laser-material interaction code that models the behavior of excited electrons in the semiconductor. These simulations are programmed and run on computer servers at KSU. Prior to each simulation, we vary the color and intensity of the laser pulse and observe how these might affect the damage process. We find that, at specific combinations of these parameters, the wire’s energy density and temperature exceed its melting point, which will cause irreversible damage to the structure. To provide an experimental test of our model, we also record the electric current generated by the process and any lingering electromagnetic radiation from the wire after the laser pulse’s departure.