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Characterization of Carrier Cooling Bottleneck in Silicon Nanoparticles by Extreme Ultraviolet (XUV) Transient Absorption Spectroscopy

Porter, Ilana J. and Lee, Angela and Cushing, Scott K. and Chang, Hung-Tzu and Ondry, Justin C. and Alivisatos, A. Paul and Leone, Stephen R. (2021) Characterization of Carrier Cooling Bottleneck in Silicon Nanoparticles by Extreme Ultraviolet (XUV) Transient Absorption Spectroscopy. . (Unpublished)

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Silicon nanoparticles have the promise to surpass the theoretical efficiency limit of single-junction silicon photovoltaics by the creation of a "phonon bottleneck", a theorized slowing of the cooling rate of hot optical phonons that in turn reduces the cooling rate of hot carriers in the material. To verify the presence of a phonon bottleneck in silicon nanoparticles requires simultaneous resolution of electronic and structural changes at short timescales. Here, extreme ultraviolet transient absorption spectroscopy is used to observe the excited state electronic and lattice dynamics in polycrystalline silicon nanoparticles following 800 nm photoexcitation, which excites carriers with 0.35 ± 0.03 eV excess energy above the Δ₁ conduction band minimum. The nanoparticles have nominal 100 nm diameters with crystalline grain sized of about ~16 nm. The extracted carrier-phonon and phonon-phonon relaxation times of the nanoparticles are compared to those for a silicon (100) single crystal thin film at similar carrier densities (2 x 10¹⁹ cm⁻³ for the nanoparticles and 6 x 10¹⁹ cm⁻³ for the thin film). The measured carrier-phonon and phonon-phonon scattering lifetimes for the polycrystalline nanoparticles are 870 ± 40 fs and 17.5 ± 0.3 ps, respectively, versus 195±20 fs and 8.1 ± 0.2 ps, respectively, for the silicon thin film. The reduced scattering rates observed in the nanoparticles are consistent with the phonon bottleneck hypothesis.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Porter, Ilana J.0000-0001-8692-9950
Lee, Angela0000-0001-5388-8400
Cushing, Scott K.0000-0003-3538-2259
Chang, Hung-Tzu0000-0001-7378-8212
Ondry, Justin C.0000-0001-9113-3420
Alivisatos, A. Paul0000-0001-6895-9048
Leone, Stephen R.0000-0003-1819-1338
Additional Information:Attribution 4.0 International (CC BY 4.0). This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract No. DE-AC02-05-CH11231 within the Physical Chemistry of Inorganic Nanostructures Program (KC3103). S.K.C. acknowledges support by the Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE) Postdoctoral Research Award under the EERE Solar Energy Technologies Office. H.-T. C. acknowledges support from Air Force Office of Scientific Research (AFOSR) (FA9550-15-1-0037 and FA9550-19-1-0314) and W. M. Keck Foundation (No. 046300). J.C.O. gratefully acknowledges the support of the Kavli Energy NanoScience Institute / Philomathia Graduate Student Fellowship. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The authors gratefully acknowledge mentorship and guidance from Lucas M. Carneiro.
Funding AgencyGrant Number
Department of Energy (DOE)DE-AC02-05-CH11231
Air Force Office of Scientific Research (AFOSR)FA9550-15-1-0037
Air Force Office of Scientific Research (AFOSR)FA9550-19-1-0314
W. M. Keck Foundation046300
Kavli Energy Nanoscience InstituteUNSPECIFIED
Record Number:CaltechAUTHORS:20220816-192451845
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:116323
Deposited By: George Porter
Deposited On:16 Aug 2022 22:56
Last Modified:02 Jun 2023 01:16

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