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Macroscale and Nanoscale Photoelectrochemical Behavior of p-Type Si(111) Covered by a Single Layer of Graphene or Hexagonal Boron Nitride

Thompson, Annelise C. and Simpson, Burton H. and Lewis, Nathan S. (2020) Macroscale and Nanoscale Photoelectrochemical Behavior of p-Type Si(111) Covered by a Single Layer of Graphene or Hexagonal Boron Nitride. ACS Applied Materials & Interfaces, 12 (10). pp. 11551-11561. ISSN 1944-8244.

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[img] PDF (Figures S1–S6 and Table S1 contain XPS, UPS, Raman maps, UV–vis spectra, and Tauc plots characterizing the 2D materials and 2d material coated p-Si; Figure S7 contains data for cyclic voltammetry of p-SiOx electrodes; Figure S8 and Table S2 contain...) - Supplemental Material
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Two-dimensional (2D) materials may enable a general approach to the introduction of a dipole at a semiconductor surface as well as control over other properties of the double layer at a semiconductor/liquid interface. Vastly different properties can be found in the 2D materials currently studied due in part to the range of the distribution of density-of-states. In this work, the open-circuit voltage (V_(oc)) of p-Si–H, p-Si/Gr (graphene), and p-Si/h-BN (hexagonal boron nitride) in contact with a series of one-electron outer-sphere redox couples was investigated by macroscale measurements as well as by scanning electrochemical cell microscopy (SECCM). The band gaps of Gr and h-BN (0–5.97 eV) encompass the wide range of band gaps for 2D materials, so these interfaces (p-Si/Gr and p-Si/h-BN) serve as useful references to understand the behavior of 2D materials more generally. The value of V_(oc) shifted with respect to the effective potential of the contacting solution, with slopes (ΔV_(oc)/ΔE_(Eff)) of −0.27 and −0.38 for p-Si/Gr and p-Si/h-BN, respectively, indicating that band bending at the p-Si/h-BN and p-Si/Gr interfaces responds at least partially to changes in the electrochemical potential of the contacting liquid electrolyte. Additionally, SECCM is shown to be an effective method to interrogate the nanoscale photoelectrochemical behavior of an interface, showing little spatial variance over scales exceeding the grain size of the CVD-grown 2D materials in this work. The measurements demonstrated that the polycrystalline nature of the 2D materials had little effect on the results and confirmed that the macroscale measurements reflected the junction behavior at the nanoscale.

Item Type:Article
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URLURL TypeDescription
Thompson, Annelise C.0000-0003-2414-7050
Simpson, Burton H.0000-0002-3990-6892
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2020 American Chemical Society. Received: November 20, 2019; Accepted: February 10, 2020; Published: February 10, 2020. This work was supported by the Department of Energy, Basic Energy Sciences, grant DE-FG02-03ER15483. A.C.T. acknowledges the National Science Foundation for a graduate fellowship. SECCM, UV–vis, and XPS data were collected at the Molecular Materials Research Center in the Beckman Institute of the California Institute of Technology. We gratefully acknowledge the critical support and infrastructure provided for this work by The Kavli Nanoscience Institute at Caltech. Author Contributions: The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. A.C.T. and B.H.S. contributed equally. The authors declare no competing financial interest.
Group:Kavli Nanoscience Institute
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-03ER15483
NSF Graduate Research FellowshipUNSPECIFIED
Subject Keywords:2D material, graphene, hexagonal boron nitride, photoelectrochemistry, semiconductor/liquid junction, scanning electrochemical cell microscopy
Issue or Number:10
Record Number:CaltechAUTHORS:20200211-081431977
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Official Citation:Macroscale and Nanoscale Photoelectrochemical Behavior of p-Type Si(111) Covered by a Single Layer of Graphene or Hexagonal Boron Nitride. Annelise C. Thompson, Burton H. Simpson, and Nathan S. Lewis. ACS Applied Materials & Interfaces 2020 12 (10), 11551-11561; DOI: 10.1021/acsami.9b21134
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:101218
Deposited By: Tony Diaz
Deposited On:11 Feb 2020 17:08
Last Modified:16 Mar 2020 18:04

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