A proof of concept of the bulk photovoltaic effect in non-uniformly strained silicon

We numerically investigate non-uniformly strained Si-based systems to demonstrate that when a well focused laser beam locally excites the sample, the lattice distortion, impacting the band edge profile, causes a spatially dependent photovoltaic effect. It follows that, scanning the sample surface wi...

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Bibliographic Details
Published in:Journal of applied physics 2022-03, Vol.131 (12)
Main Authors: Manganelli, C. L., Kayser, S., Virgilio, M.
Format: Article
Language:English
Subjects:
Applied physics
Crystal lattices
Deformation effects
Laser beams
Photovoltaic effect
Potential theory
Robustness (mathematics)
Room temperature
Scanning
Semiconductor crystals
Silicon
Strain analysis
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Summary:We numerically investigate non-uniformly strained Si-based systems to demonstrate that when a well focused laser beam locally excites the sample, the lattice distortion, impacting the band edge profile, causes a spatially dependent photovoltaic effect. It follows that, scanning the sample surface with the pump spot, a photovoltage signal can be acquired and used to quantitatively map the non-uniform strain field. To provide numerical evidence in this direction, we combine mechanical simulations with deformation potential theory to estimate the band edge energy landscape of a Si lattice strained by an array of SiN stripes fabricated on the top surface. These data are then used to simulate the voltage signal obtained scanning the sample surface with a normal incident pump beam. Our analysis suggests that strain deformations as small as 0.1% can trigger at room temperature robust photovoltaic signals. These results allow us to envision the development of a fast, cost-effective, and non-destructive setup, which leverages on the bulk-photovoltaic effect to image the lattice deformation in semiconductor crystals.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0074426