• Mebed, Abdelazim M.
• Abd-Elnaiem, Alaa M.
• Malsche, Wim De

Abstract

<p>Nanoporous silicon (NPS) with mesopores size (2–50 nm) formed by anodization of highly doped p-type silicon at specific anodizing conditions is highly needed for technological applications. However, the surface of the NPS was rapidly oxidized upon exposure to the atmosphere due to the presence of boron. Therefore, there is a need for the leaching of the boron from the NPS surface. In the present work, the NPS layers with mesopores size were synthesized by anodizing highly doped p-type silicon, and then the boron impurity was leached by a wet chemical etching method. The consumed charge and other important characteristics during the anodization are monitored and summarized. The influence of anodizing time on the electric behavior of NPS was further investigated and displayed. The boron leaching impact on the NPS cell performance is reported and characterized by electrochemical impedance spectroscopy (EIS). The EIS measurements were carried out for NPS layers with different thicknesses, leached boron, and nonporous silicon samples. In this context, the change in boron leached and NPS morphology with leaching time was investigated by scanning electron microscope (SEM) and EIS measurements to explain the quantitative impact of that removal on its performance to be used as photoelectric devices. We hypothesize that the boron-leached layer could acts as anti-reflective coatings and assists in the passivation of the surface, which affected the results of the EIS measurements. The boron-leached thin layer could be considered as tunneling interfacial regions between the NPS layer and the front connection.</p>

Topics

• morphology
• surface
• scanning electron microscopy
• Silicon
• etching
• Boron
• leaching
• electrochemical-induced impedance spectroscopy