Supercritical fluid electrodeposition of elemental germanium onto titanium nitride substrates
Supercritical fluid electrodeposition of elemental germanium onto titanium nitride substrates
We report the electrodeposition of germanium from supercritical difluoromethane (sc-CH2F2) at 19 MPa and 358 K using [NnBu4][GeCl3]. Voltammetry shows a classic nucleation loop on the first anodic scan with a high nucleation overpotential for germanium on TiN. In all cases the deposition appears to be kinetically limited by a coupled, potential independent, chemical step. Films of germanium were deposited at a range of potentials. At high overpotentials the films were dendritic and poorly adherent. At lower overpotentials, below ?2 V vs. Ag|LaF3, the films are smoother and more homogeneous. Analysis of the films by energy dispersive X-ray (EDX) spectroscopy shows the presence of germanium with some chloride impurity. Raman spectroscopy confirms the deposition of amorphous germanium. Plating by pulsing to ?1.9 V vs. Ag|LaF3 for 100 ms and then growth at ?1.5 V vs. Ag|LaF3, was found to produce the best films. On annealing at 700°C under an Ar atmosphere for 1 hour the as-deposited amorphous germanium film is converted into crystalline germanium, as determined by X-ray diffraction (XRD) and Raman spectroscopy.
difluoromethane, electrodeposition, germanium, supercritical fluid, titanium nitride
D619-D624
Cummings, Charlie
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Bartlett, Philip N.
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Pugh, David
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Reid, Gillian
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Levason, William
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Hasan, Mahboba M.
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Hector, Andrew L.
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Spencer, Joe
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Smith, David C.
d9b2c02d-b7ea-498b-9ea1-208a1681536f
16 October 2015
Cummings, Charlie
37ed515b-eb09-4c6b-9c66-61013c8c132a
Bartlett, Philip N.
d99446db-a59d-4f89-96eb-f64b5d8bb075
Pugh, David
9ec61267-ae4d-40d8-bebf-0d603e2588d3
Reid, Gillian
37d35b11-40ce-48c5-a68e-f6ce04cd4037
Levason, William
e7f6d7c7-643c-49f5-8b57-0ebbe1bb52cd
Hasan, Mahboba M.
fdb892ba-7f72-4e59-98c1-f070733840c9
Hector, Andrew L.
f19a8f31-b37f-4474-b32a-b7cf05b9f0e5
Spencer, Joe
a6c29a03-e851-4598-a565-6a92bb581e70
Smith, David C.
d9b2c02d-b7ea-498b-9ea1-208a1681536f
Cummings, Charlie, Bartlett, Philip N., Pugh, David, Reid, Gillian, Levason, William, Hasan, Mahboba M., Hector, Andrew L., Spencer, Joe and Smith, David C.
(2015)
Supercritical fluid electrodeposition of elemental germanium onto titanium nitride substrates.
Journal of the Electrochemical Society, 162 (14), .
(doi:10.1149/2.0771514jes).
Abstract
We report the electrodeposition of germanium from supercritical difluoromethane (sc-CH2F2) at 19 MPa and 358 K using [NnBu4][GeCl3]. Voltammetry shows a classic nucleation loop on the first anodic scan with a high nucleation overpotential for germanium on TiN. In all cases the deposition appears to be kinetically limited by a coupled, potential independent, chemical step. Films of germanium were deposited at a range of potentials. At high overpotentials the films were dendritic and poorly adherent. At lower overpotentials, below ?2 V vs. Ag|LaF3, the films are smoother and more homogeneous. Analysis of the films by energy dispersive X-ray (EDX) spectroscopy shows the presence of germanium with some chloride impurity. Raman spectroscopy confirms the deposition of amorphous germanium. Plating by pulsing to ?1.9 V vs. Ag|LaF3 for 100 ms and then growth at ?1.5 V vs. Ag|LaF3, was found to produce the best films. On annealing at 700°C under an Ar atmosphere for 1 hour the as-deposited amorphous germanium film is converted into crystalline germanium, as determined by X-ray diffraction (XRD) and Raman spectroscopy.
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Accepted/In Press date: 29 September 2015
Published date: 16 October 2015
Keywords:
difluoromethane, electrodeposition, germanium, supercritical fluid, titanium nitride
Organisations:
Chemistry
Identifiers
Local EPrints ID: 385448
URI: http://eprints.soton.ac.uk/id/eprint/385448
ISSN: 0013-4651
PURE UUID: 67d87ede-d5ff-4caf-957d-36a561bab2a4
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Date deposited: 20 Jan 2016 09:03
Last modified: 15 Mar 2024 02:52
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Author:
Charlie Cummings
Author:
David Pugh
Author:
Mahboba M. Hasan
Author:
Joe Spencer
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