Nanometer-Thick Gold on Silicon as a Proxy for Single-Crystal Gold for the Electrodeposition of Epitaxial Cuprous Oxide Thin Films
- Department of Chemistry and Graduate Center for Materials Research, Missouri University of Science and Technology, Rolla, Missouri 65409-1170, United States, and
- Department of Materials Science and Engineering and Graduate Center for Materials Research, Missouri University of Science and Technology, Rolla, Missouri 65409-1170, United States
Here, single-crystal Au is an excellent substrate for electrochemical epitaxial growth due to its chemical inertness, but the high cost of bulk Au single crystals prohibits their use in practical applications. Here, we show that ultrathin epitaxial films of Au electrodeposited onto Si(111), Si(100), and Si(110) wafers can serve as an inexpensive proxy for bulk single-crystal Au for the deposition of epitaxial films of cuprous oxide (Cu2O). The Au films range in thickness from 7.7 nm for a film deposited for 5 min to 28.3 nm for a film deposited for 30 min. The film thicknesses are measured by low-angle X-ray reflectivity and X-ray Laue oscillations. High-resolution TEM shows that there is not an interfacial SiOx layer between the Si and Au. The Au films deposited on the Si(111) substrates are smoother and have lower mosaic spread than those deposited onto Si(100) and Si(110). The mosaic spread of the Au(111) layer on Si(111) is only 0.15° for a 28.3 nm thick film. Au films deposited onto degenerate Si(111) exhibit ohmic behavior, whereas Au films deposited onto n-type Si(111) with a resistivity of 1.15 Ω·cm are rectifying with a barrier height of 0.85 eV. The Au and the Cu2O follow the out-of-plane and in-plane orientations of the Si substrates, as determined by X-ray pole figures. The Au and Cu2O films deposited on Si(100) and Si(110) are both twinned. The films grown on Si(100) have twins with a [221] orientation, and the films grown on Si(110) have twins with a [411] orientation. An interface model is proposed for all Si orientations, in which the –24.9% mismatch for the Au/Si system is reduced to only +0.13% by a coincident site lattice in which 4 unit meshes of Au coincide with 3 unit meshes of Si. Although this study only considers the deposition of epitaxial Cu2O films on electrodeposited Au/Si, the thin Au films should serve as high-quality substrates for the deposition of a wide variety of epitaxial materials.
- Research Organization:
- Missouri Univ. of Science and Technology, Rolla, MO (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- FG02-08ER46518
- OSTI ID:
- 1256140
- Alternate ID(s):
- OSTI ID: 1258615
- Journal Information:
- ACS Applied Materials and Interfaces, Journal Name: ACS Applied Materials and Interfaces Vol. 8 Journal Issue: 24; ISSN 1944-8244
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Epitaxial (111) films of Cu, Ni, and Cu{sub x}Ni{sub y} on {alpha}-Al{sub 2}O{sub 3} (0001) for graphene growth by chemical vapor deposition
Epitaxial Electrodeposition of Methylammonium Lead Iodide Perovskites