The Role of the Reduction of ITO on the Electrical Properties of the p-i Junction: A Thin SiO Layer as a Remedy

Abstract

The reduction of the ITO by the deposition of an a-Si:C:H p layer by means of a Plasma Enhanced Chemical Vapour Deposition (PECVD), is considerably diminished if a thin silicon monoxide layer (estimated to be between 5–50Å thick) is applied as a diffusion barrier. The amount of reduced indium diminishes (its concentration is two times lower), while the amount of silicon oxide is less although silicon monoxide was added on purpose. The influence of the silicon monoxide layer on the electrical properties of the p-i junction is shown by its I–V curves (in the dark and under illumination). We can see that with a suitable silicon monoxide thickness we can improve the short circuit current density (J_sc) and the rectifying ratio, while the value of the open circuit voltage (V_oc) is practically the same.