Tengeler, Sven ; Fingerle, Mathias ; Calvet, Wolfram ; Steinert, Céline ; Kaiser, Bernhard ; Mayer, Thomas ; Jaegermann, Wolfram (2018)
The Impact of Different Si Surface Terminations in the (001) n-Si/NiOx Heterojunction on the Oxygen Evolution Reaction (OER) by XPS and Electrochemical Methods.
In: Journal of The Electrochemical Society, 165 (4)
doi: 10.1149/2.0151804jes
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
The interaction between (001) n-Si and NiOx was investigated with regard to the oxygen evolution reaction (OER), applicable either for water splitting or CO2 reduction. Thin layers of nickel oxide were deposited step by step by reactive sputter deposition and analyzed in-situ after each step using X-ray photoelectron spectroscopy (XPS). This was performed for silicon with different surface preparations: H-termination, thermally grown oxide (2 Å) and a monolayer of native oxide (4 Å). Upon contact formation the initial flatband like situation in the Si substrates changed to a 0.35 to 0.4 eV upward band bending for all three heterojunctions, with an alignment of the valence bands favorable to hole extraction. With near identical heterojunction performance and identical NiOx catalyst layers (η(10 mA/cm2) = 0.44 ± 0.01 V vs. RHE on Ni) an equally identical performance for the OER would be expected. While the native oxide covered sample shows the expected performance in cyclic voltammetry measurements the others fall short of expectations. Using chopped light measurements, this under-performance could be attributed to a higher density of defect states at the silicon surface. Apparently a 4Å SiO2 layer is sufficient protection to prevent the formation of defect states during NiOx deposition, thinner protective layers or none at all result in increased defect states, while thicker layers perform poorly due to their high resistance.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2018 |
| Autor(en): | Tengeler, Sven ; Fingerle, Mathias ; Calvet, Wolfram ; Steinert, Céline ; Kaiser, Bernhard ; Mayer, Thomas ; Jaegermann, Wolfram |
| Art des Eintrags: | Bibliographie |
| Titel: | The Impact of Different Si Surface Terminations in the (001) n-Si/NiOx Heterojunction on the Oxygen Evolution Reaction (OER) by XPS and Electrochemical Methods |
| Sprache: | Englisch |
| Publikationsjahr: | 17 Januar 2018 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Journal of The Electrochemical Society |
| Jahrgang/Volume einer Zeitschrift: | 165 |
| (Heft-)Nummer: | 4 |
| DOI: | 10.1149/2.0151804jes |
| URL / URN: | https://doi.org/10.1149/2.0151804jes |
| Kurzbeschreibung (Abstract): | The interaction between (001) n-Si and NiOx was investigated with regard to the oxygen evolution reaction (OER), applicable either for water splitting or CO2 reduction. Thin layers of nickel oxide were deposited step by step by reactive sputter deposition and analyzed in-situ after each step using X-ray photoelectron spectroscopy (XPS). This was performed for silicon with different surface preparations: H-termination, thermally grown oxide (2 Å) and a monolayer of native oxide (4 Å). Upon contact formation the initial flatband like situation in the Si substrates changed to a 0.35 to 0.4 eV upward band bending for all three heterojunctions, with an alignment of the valence bands favorable to hole extraction. With near identical heterojunction performance and identical NiOx catalyst layers (η(10 mA/cm2) = 0.44 ± 0.01 V vs. RHE on Ni) an equally identical performance for the OER would be expected. While the native oxide covered sample shows the expected performance in cyclic voltammetry measurements the others fall short of expectations. Using chopped light measurements, this under-performance could be attributed to a higher density of defect states at the silicon surface. Apparently a 4Å SiO2 layer is sufficient protection to prevent the formation of defect states during NiOx deposition, thinner protective layers or none at all result in increased defect states, while thicker layers perform poorly due to their high resistance. |
| Freie Schlagworte: | interface, OER, XPS |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Oberflächenforschung |
| Hinterlegungsdatum: | 22 Feb 2018 13:33 |
| Letzte Änderung: | 26 Jun 2018 11:03 |
| PPN: | |
| Sponsoren: | Financial support through the a-leaf project (732840-A-LEAF) by the European Union is gratefully acknowledged., As well as from the project ’fundamentals of electrochemical phase boundaries at semiconductor/electrolyte interfaces’ GEP-HE (13XP5023A) funded by the German Federal Ministry of Education and Research BMB., Funding from the German science foundation excellency graduate school ‘Energy Science and Engineering’ (GSC 1070) is gratefully acknowledged. |
| Export: | |
| Suche nach Titel in: | TUfind oder in Google |
 |
Frage zum Eintrag |
Optionen (nur für Redakteure)
 |
Redaktionelle Details anzeigen |
Drucken
Impressum