Dependence of Electrical Response on Etching Time of Calmodulin-Surface-Functionalized Porous Silicon Based Bi-Parametric Calcium Detector

In this work, the dependence of the electrical response upon the etching time of calmodulin (CaM) functionalized porous silicon (PSi) based calcium detecting platform is studied. Psi, due to its high surface area, remarkable absorption capability, and biocompatibility, finds great application as a biosensor. Here, an electrochemical etching process is employed to fabricate PSi on a P-type silicon wafer, which is further CaM surface functionalized for effective calcium attachment. The electrical sensitivity that is the current versus voltage and the capacitance versus input voltage frequency of the PSi-based calcium detecting platform is monitored with increasing electrochemical etching time and a substantial change in electrical sensitivity is observed. Analysis was performed for both nano-porous and macro-porous PSi-based calcium detectors and significant variation of electrical response was observed in both cases with varying etching time. This work can be employed to substantially increase the sensitivity of PSi-based electrical calcium detectors. The findings of this work may find use in effective fabrication and design, together with optimization of highly sensitive PSi-based chemical and ionic and biosensors.