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Thomas ELH, Mandal S, Ashek-I-Ahmed, Macdonald JE, Dane TG, Rawle J, Cheng CL, Williams OA. Spectroscopic Ellipsometry of Nanocrystalline Diamond Film Growth. ACS OMEGA 2017; 2:6715-6727. [PMID: 31457263 PMCID: PMC6645230 DOI: 10.1021/acsomega.7b00866] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/19/2017] [Indexed: 07/25/2023]
Abstract
With the retention of many of the unrivaled properties of bulk diamond but in thin-film form, nanocrystalline diamond (NCD) has applications ranging from micro-/nano-electromechanical systems to tribological coatings. However, with Young's modulus, transparency, and thermal conductivity of films all dependent on the grain size and nondiamond content, compositional and structural analysis of the initial stages of diamond growth is required to optimize growth. Spectroscopic ellipsometry (SE) has therefore been applied to the characterization of 25-75 nm thick NCD samples atop nanodiamond-seeded silicon with a clear distinction between the nucleation and bulk growth regimes discernable. The resulting presence of an interfacial carbide and peak in nondiamond carbon content upon coalescence is correlated with Raman spectroscopy, whereas the surface roughness and microstructure are in accordance with values provided by atomic force microscopy. As such, SE is demonstrated to be a powerful technique for the characterization of the initial stages of growth and hence the optimization of seeding and nucleation within films to yield high-quality NCD.
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Affiliation(s)
- Evan L. H. Thomas
- School
of Physics and Astronomy, Cardiff University, Queen’s Buildings, The Parade, Cardiff CF24 3AA, U.K.
| | - Soumen Mandal
- School
of Physics and Astronomy, Cardiff University, Queen’s Buildings, The Parade, Cardiff CF24 3AA, U.K.
| | - Ashek-I-Ahmed
- Department
of Physics, National Dong Hwa University, Hualien 97401, Taiwan
| | - John Emyr Macdonald
- School
of Physics and Astronomy, Cardiff University, Queen’s Buildings, The Parade, Cardiff CF24 3AA, U.K.
| | - Thomas G. Dane
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Jonathan Rawle
- Diamond
Light Source, Beamline I07, Harwell Science & Innovation Campus, Didcot OX11 0DE, U.K.
| | - Chia-Liang Cheng
- Department
of Physics, National Dong Hwa University, Hualien 97401, Taiwan
| | - Oliver A. Williams
- School
of Physics and Astronomy, Cardiff University, Queen’s Buildings, The Parade, Cardiff CF24 3AA, U.K.
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Seshan V, Murthy DHK, Castellanos-Gomez A, Sachdeva S, Ahmad HA, Janssens SD, Janssen W, Haenen K, van der Zant HSJ, Sudhölter EJR, Savenije TJ, de Smet LCPM. Contactless photoconductance study on undoped and doped nanocrystalline diamond films. ACS APPLIED MATERIALS & INTERFACES 2014; 6:11368-11375. [PMID: 24918631 DOI: 10.1021/am501907q] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Hydrogen and oxygen surface-terminated nanocrystalline diamond (NCD) films are studied by the contactless time-resolved microwave conductivity (TRMC) technique and X-ray photoelectron spectroscopy (XPS). The optoelectronic properties of undoped NCD films are strongly affected by the type of surface termination. Upon changing the surface termination from oxygen to hydrogen, the TRMC signal rises dramatically. For an estimated quantum yield of 1 for sub-bandgap optical excitation the hole mobility of the hydrogen-terminated undoped NCD was found to be ∼0.27 cm(2)/(V s) with a lifetime exceeding 1 μs. Assuming a similar mobility for the oxygen-terminated undoped NCD a lifetime of ∼100 ps was derived. Analysis of the valence band spectra obtained by XPS suggests that upon oxidation of undoped NCD the surface Fermi level shifts (toward an increased work function). This shift originates from the size and direction of the electronic dipole moment of the surface atoms, and leads to different types of band bending at the diamond/air interface in the presence of a water film. In the case of boron-doped NCD no shift of the work function is observed, which can be rationalized by pinning of the Fermi level. This is confirmed by TRMC results of boron-doped NCD, which show no dependency on the surface termination. We suggest that photoexcited electrons in boron-doped NCD occupy nonionized boron dopants, leaving relatively long-lived mobile holes in the valence band.
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Affiliation(s)
- Venkatesh Seshan
- Department of Chemical Engineering, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands
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Zhong YL, Ng W, Yang JX, Loh KP. Electrostatically Self-Assembled Polyoxometalates on Molecular-Dye-Functionalized Diamond. J Am Chem Soc 2009; 131:18293-8. [DOI: 10.1021/ja908131t] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yu Lin Zhong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Wibowo Ng
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Jia-Xiang Yang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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Remes Z, Nesladek M, Haenen K, Watanabe K, Taniguchi T. The optical absorption and photoconductivity spectra of hexagonal boron nitride single crystals. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/pssa.200561902] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hounsome LS, Jones R, Martineau PM, Shaw MJ, Briddon PR, Öberg S, Blumenau AT, Fujita N. Optical properties of vacancy related defects in diamond. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/pssa.200561914] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Haenen K, Meykens K, Nesládek M, Knuyt G, Quaeyhaegens C, Stals LM, Koizumi S, Gheeraert E. Low Temperature Photoconductivity Detection of Phosphorus in Diamond. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1521-396x(199907)174:1<53::aid-pssa53>3.0.co;2-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Haenen K, Meykens K, Nesládek M, Stals LM, Teraji T, Koizumi S, Gheeraert E. Study of the Electronic Structure of the Phosphorus Level in n-Type CVD Diamond. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1521-396x(199907)174:13.0.co;2-c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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