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Picosecond carrier dynamics in InAs and GaAs revealed by ultrafast electron microscopy
Christopher Perez1,2, Scott R Ellis1,3, Francis M Alcorn1
1Sandia National Laboratories, Livermore, CA, USA.
Science Advances
|May 15, 2024
Summary
Investigating ultrafast carrier dynamics in III-V semiconductors reveals a common 100 ps timescale, suggesting fundamental kinetic limits for optoelectronic devices. This finding aids in designing faster, smaller components.
Area of Science:
- Materials Science
- Semiconductor Physics
- Optoelectronics
Background:
- Understanding carrier dynamics in III-V semiconductors is crucial for advanced optoelectronic devices.
- Identifying factors limiting spatiotemporal carrier behavior has been challenging.
Purpose of the Study:
- To investigate the limits of spatiotemporal carrier dynamics in III-V semiconductors.
- To simultaneously measure carrier dynamics with related electronic properties.
Main Methods:
- Utilized scanning ultrafast electron microscopy (SUEM).
- Measured picosecond carrier dynamics, subsurface band bending, surface potentials, and trap densities in n-GaAs and p-InAs.
Main Results:
- Observed an unexpected negative-time contrast in secondary electrons.
- Found carrier dynamics in n-GaAs and p-InAs occur on a common ~100 ps timescale, irrespective of material properties.
Conclusions:
- The common timescale suggests fundamental kinetic limits in III-V semiconductors.
- Highlights the need for techniques that simultaneously probe electro-optical properties for device design.
