Hydrogen ion diffusion coefficient of a hydrogenated amorphous silicon thin film

Abstract

Hydrogen ion diffusion in a hydrogenated amorphous silicon thin film is of significant interest because of its importance in semiconductor, sensor and solar cell coating applications. In this study, a novel method based on potential–pH response measurement was used to determine hydrogen ion diffusion in a hydrogenated amorphous silicon thin film. The drift in the potential–pH response is believed to be due to the hydrated layer, which affects hydrogen ion diffusion on to the gate of ion sensitive field effect transistors (ISFETs). The hydrogen ion diffusion coefficient of a hydrogenated amorphous silicon film obtained from this method was 3 × 10⁻¹⁷ cm² s⁻¹. The unique feature of the potential–pH response method is its relatively simple experimental procedure, which eliminates complications arising from surface related effects and/or presence of hydrogen traps in membranes such as those found in the conventional permeation method.