Ultrafast strain-induced current in a GaAs Schottky diode

Area of Science:

• Solid-state physics
• Optoelectronics
• Materials science

Background:

• Femtosecond laser excitation of metal films generates picosecond acoustic pulses.
• These acoustic pulses can interact with semiconductor devices, such as gallium arsenide (GaAs) based Schottky diodes.
• Understanding transient current generation in these systems is crucial for high-speed electronic applications.

Purpose of the Study:

• To investigate the generation of transient currents in a GaAs/Au Schottky diode induced by picosecond acoustic pulses.
• To analyze the contributions of different physical mechanisms, including strain pulse interaction with the depletion layer edge and the GaAs/Au interface, to the observed current.
• To develop and validate a theoretical model for the strain pulse-induced current component.

Main Methods:

• Excitation of a metal film using femtosecond laser pulses to generate picosecond acoustic pulses.
• Measurement of the induced transient current in a GaAs/Au Schottky diode with subnanosecond rise time.
• Development of a theoretical model to describe the strain pulse interaction with the depletion layer edge in GaAs.

Main Results:

• Observed a transient current with subnanosecond rise time in the GaAs/Au Schottky diode upon laser excitation.
• Identified distinct signal components attributed to the strain pulse interaction at the depletion layer edge and the GaAs/Au interface.
• Demonstrated excellent agreement between the experimental results and the proposed theoretical model for the depletion layer component.

Conclusions:

• Picosecond acoustic pulses effectively induce measurable transient currents in GaAs/Au Schottky diodes.
• The strain pulse's interaction with the depletion layer edge is a significant factor in current generation.
• The developed theoretical model accurately describes the strain pulse-induced current, providing valuable insights into optoelectronic device physics.