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The electrochemical reactivity and suitability of hexachlorodisilane and tetrakis(trichlorosilyl)silane as Si ec-LLS electrodeposition precursors in several electrolyte solutions have been investigated. Voltammetric data indicated that perchlorinated silanes exhibit mechanistically similar electrochemical responses as SiCl4, regardless of the Si–Si bond content in the precursor. The voltammetric responses were a strong function of the concentration of the precursor, indicating the participation of electrogenerated intermediates during the reduction and concomitant Si electrodeposition. Variation of the anion in the supporting electrolyte was found to be a critical factor for the thermal and chemical stability of the precursor bath. A combination of chronoamperometry and electron microscopy data were used to study the deposition efficiency specifically for hexachlorodisilane. The faradaic efficiency was low, regardless of overpotential or the composition of the electrolyte. Cumulatively, these data show that while larger chlorosilanes can be used for conventional Si electrodeposition over a wider range of conditions, their chemical instability and propensity for low faradaic efficiency limit their utility as reagents relative to SiCl4for Si electrodeposition by ec-LLS.
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Electrodeposition Parameters Dramatically Influence the Morphology, Stability, and Performance of n‐Si/Pt Light‐Addressable Electrochemical Sensors
Abstract Light addressable electrochemical (LAE) sensors have seen great utility in the past several years because they enable multiple localized electrochemical measurements to be performed on a single macroscopic electrode, opening up applications in imaging, biosensing, surface patterning, and multiplexing. In this study, we investigated the effects of electrodeposition on the formation of LAE sensors formed between n‐Si and electrodeposited Pt. We prepared sensors by electrodepositing Pt onto freshly‐etched n‐Si under a variety of conditions, varying the Pt precursor concentration, electrodeposition time, supporting electrolyte, and potential waveform. We characterized the sensors using a combination of atomic force microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. This study shows that the electrodeposition parameters have a dramatic impact on the morphology of the electrodeposited surfaces, sensor stability, and sensitivity towards H2O2. Specifically, we observed that continuous Pt films prepared with a higher Pt precursor concentration were more stable and had better linearity, higher sensitivity, and broader dynamic range than those prepared with a lower Pt precursor concentration. The stability and increased H2O2sensing performance correlate strongly with an increase in the Pt islands which make up the film. These data highlight that the morphology of the metal in semiconductor/metal junction LAE sensors has an impact on important performance metrics like stability and sensitivity. They also demonstrate the need for semiconductor/metal LAE sensors to be studied using micro‐ and nanoscale imaging techniques in order to more deeply understand their performance characteristics.
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- Award ID(s):
- 1944432
- PAR ID:
- 10473427
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemElectroChem
- Volume:
- 10
- Issue:
- 23
- ISSN:
- 2196-0216
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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