A Mott-Schottky analysis of mesoporous silicon in aqueous electrolyte solution by electrochemical impedance spectroscopy

Brinker, Manuel; Huber, Patrick

doi:10.1016/j.electacta.2024.144038

Journal Article

PUBDB-2024-01466

A Mott-Schottky analysis of mesoporous silicon in aqueous electrolyte solution by electrochemical impedance spectroscopy

Brinker, M.Extern*DESY* ; Huber, P. (Corresponding author)Extern*DESY*

2024
Elsevier New York, NY [u.a.]

Electrochimica acta 483, 144038 (2024) [10.1016/j.electacta.2024.144038]

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Please use a persistent id in citations: doi:10.1016/j.electacta.2024.144038 doi:10.3204/PUBDB-2024-01466

Report No.: arXiv:2312.04252

Abstract: Nanoporosity in silicon leads to completely new functionalities of this mainstream semiconductor.In recent years, it has been shown that filling the pores with aqueous electrolytes in addition opensa particularly wide field for modifying and achieving active control of these functionalities, e.g.,for electrochemo-mechanical actuation and tunable photonics, or for the design of on-chip superca-pacitors. However, a mechanistic understanding of these new features has been hampered by thelack of a detailed characterization of the electrochemical behavior of mesoporous silicon in aqueouselectrolytes. Here, the capacitive, potential-controlled charging of the electrical double layer in amesoporous silicon electrode (pore diameter 7 nm) imbibed with perchloric acid solution is studiedby electrochemical impedance spectroscopy. Thorough measurements with detailed explanationsof the observed phenomena lead to a comprehensive understanding of the capacitive properties ofporous silicon. An analysis based on the Mott-Schottky equation allows general conclusions to bedrawn about the state of the band structure within the pore walls. Essential parameters such as theflat band potential, the doping density and the width of the space charge region can be determined.A comparison with bulk silicon shows that the flat band potential in particular is significantly al-tered by the introduction of nanopores, as it shifts from 1.4 ± 0.1 V to 1.9 ± 0.2 V. Overall, thisstudy provides a unique insight into the electrochemical processes, especially the electrical doublelayer charging, of nanoporous semiconductor electrodes.

Classification:

ddc:540

Note: 5 pages, 3 figures

Contributing Institute(s):

CIMMS-RA Center for integr. Multiscale M (CIMMS)

Research Program(s):

Experiment(s):

No specific instrument

Appears in the scientific report 2024

Database coverage:
Medline

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Creative Commons Attribution-NonCommercial CC BY-NC 4.0

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