Effect of iodide ions on the hydrogen-terminated and partially oxygen-terminated diamond surface

The effect of I- ions on the threshold voltages of the electrolyte-solution-gate diamond field-effect transistors (SGFETs) in KI solution is investigated. The threshold voltages of hydrogen-terminated (H-terminated) diamond SGFETs shift in the KI concentration range of 10(-6)-10(-1) M in aqueous solutions. The sensitivity of the H-ten-ninated diamond surface to I- ions is higher than that to Cl- or Br- ions. However, the sensitivity to I- ions of the partially oxygen-terminated (O-terminated) diamond surface drastically decreases with ozone treatment. The mechanisms of these phenomena can be explained by the surface charge and the adsorbability of I- ions on the H-terminated and O-terminated diamond surfaces. (C) 2003 Elsevier Science B.V. All rights reserved.