pH‑EGFET sensor based on the surface modification of MacroPSi with Au-NPs

Abstract

Abstract A heterostructure of (Au-NPs/MacroPSi) was synthesized by filtering a colloidal of gold nanoparticles (Au-NPs) into MacroPSi layer using high voltage electrophoretic deposition (HVEPD). The aim of that is to enhance the performance of MacroPSi used as a pH-EGFET sensor. For this purpose, the MacroPSi with an average pore size of 1.388 µm was synthesized by anodic etching of Si wafer, and a spherical shape of Au-NPs with size varied in the range of 5 to 25 nm were synthesized in ethanol by pulsed laser ablation in liquid (PLAL) technique. The density of (Au-NPs) on the surface and inside the pores of MacroPSi was determined utilizing FESEM. The pH sensitivity, linearity, and hysteresis of the heterostructure Au-NPs/MacroPSi pH-EGFET sensor were measured in the pH range from 2 to 12. The outcomes indicated that the membrane exhibited a significantly enhanced pH sensitivity value of 83.57 mV/pH with linear regression of 99.37%, and hysteresis of 3 mV and 5 mV in the acid and base pH cycles, respectively. The presence of Au-NPs improve the sensitivity and stability of the sensor due to deactivate of the Si-h surface bond and enhancement the conducting on the surface of MacroPSi, and also provide better Ohmic contact to the PSi. The research work confirms the feasibility of using the hetero structures (Au-NPs/MacroPSi) as extended get for acidity and basicity detection.