Ultrafast imaging of surface-exclusive carrier dynamics in silicon
- Creators
- Najafi, Ebrahim
- Jafari, Amir
Abstract
Understanding the dynamics of charge carriers at the semiconductor surfaces and interfaces is fundamental to the further development of photocatalytic, photovoltaic, and optoelectronic devices. Here, we study the surface photovoltage (SPV) dynamics in intrinsic and doped silicon using scanning ultrafast electron microscopy (SUEM). SUEM is a surface sensitive technique that allows the direct imaging of carriers at ultrafast time scales, thereby elucidating their spatiotemporal response to optical excitation. We first discuss the mechanism of image formation in SUEM. We then use these images to show that carrier dynamics on the silicon surface depends strongly on the doping type and concentration, though not always dictated by SPV. The numerical simulation of the drift-diffusion model suggests that this is due to the formation of complex transport processes, driven by intrinsic and photoinduced fields in the excited volume. This work refines our current understanding of the surface-exclusive dynamics in semiconductors by introducing a means to study their evolution in space and time and providing a model to explain the underlying mechanism.
Additional Information
© 2019 Published under license by AIP Publishing. Submitted: 22 October 2018; Accepted: 22 February 2019; Published Online: 10 May 2019. This work was supported by the National Science Foundation (NSF) Grant No. DMR-0964886 and Air Force Office of Scientific Research Grant No. FA9550-11-1-0055 in the Physical Biology Center for Ultrafast Science and Technology at California Institute of Technology, which is supported by the Gordon and Betty Moore Foundation.Attached Files
Published - 1.5074198.pdf
Supplemental Material - figures01.jpg
Supplemental Material - figures02.jpg
Supplemental Material - figures03.jpg
Supplemental Material - supplement_04102019_authorship_corrected_.pdf
Files
Name | Size | Download all |
---|---|---|
md5:ca4443b4228c7ae8c987ffca845539fb
|
612.8 kB | Preview Download |
md5:dcef6db45c75d1927bd7b3d7f22594fa
|
2.1 MB | Preview Download |
md5:cc1480d4daf8371bee76ff40fe1f6f40
|
250.5 kB | Preview Download |
md5:e48d36005f99d8bd34cca5ec2ff7d401
|
173.0 kB | Preview Download |
md5:2c39d9fd085f6609488401349098553f
|
88.0 kB | Preview Download |
Additional details
- Eprint ID
- 95584
- Resolver ID
- CaltechAUTHORS:20190520-075752779
- DMR-0964886
- NSF
- FA9550-11-1-0055
- Air Force Office of Scientific Research (AFOSR)
- Gordon and Betty Moore Foundation
- Created
-
2019-05-20Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field