The correlation between surface conductivity and adsorbate coverage on diamond as studied by infrared spectroscopy

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Details zur Publikation

Autor(en): Ristein J, Ley L
Zeitschrift: Diamond and Related Materials
Verlag: Elsevier
Jahr der Veröffentlichung: 2001
Band: 10
Seitenbereich: 429
ISSN: 0925-9635


Abstract

A high-resolution analysis of C-H vibrational modes on a single crystal diamond(100) surface using Fourier-transform infrared (FTIR) spectroscopy in combination with conductivity measurements is reported. On a plasma-hydrogenated diamond(100) surface, the IR spectra measured in the multiple internal reflection mode reveal three absorption lines. Two of them at 2921 and 2854 cm-1 vanish in air at an annealing temperature of 190°C and are assigned to the antisymmetric and symmetric CH2 stretching modes of a physisorbed hydrocarbon species, respectively. The third band at 2897 cm-1 has a width of 16 cm-1, is stable up to 230°C and is associated with the stretching frequency of C2H2 monohydride units on the C(100) 2 × 1:2H surface. Upon annealing in air at temperatures lower than 200°C, the surface conductivity is reversibly reduced by up to five orders of magnitude. After cooling down to room temperature, it recovers the value of 1 × 10-5 Ω-1 measured immediately after the plasma hydrogenation with a time constant of several days. Annealing at 230°C destroys the surface conductivity irreversibly and yields conductance values below the measurement limit of 5 × 10-12 Ω-1. We show that the chemisorbed hydrogen in the C2H2 configuration, together with at least one physisorbed species, is responsible for the surface conductivity of hydrogen-terminated diamond(100). © 2001 Elsevier Science B.V. All rights reserved.


FAU-Autoren / FAU-Herausgeber

Ley, Lothar Prof. Dr.
Naturwissenschaftliche Fakultät
Ristein, Jürgen apl. Prof. Dr.
Lehrstuhl für Laserphysik

Zuletzt aktualisiert 2018-09-08 um 06:09