High Sensitivity pH Sensor Based on Porous Silicon (PSi) Extended Gate Field-Effect Transistor

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Field-effect transistors (FETs) are widely used for chemical sensing.
• Developing novel materials for enhanced FET sensor performance is crucial.

Purpose of the Study:

• To prepare and evaluate porous silicon (PSi) as an extended gate field-effect transistor (EGFET) for pH sensing.
• To assess the sensitivity, stability, and hysteresis of the PSi-based sensor.

Main Methods:

• Porous silicon (PSi) was fabricated with specific pore sizes (500-750 nm) and depth (42 µm).
• The PSi material was integrated into an extended gate field-effect transistor (EGFET) configuration.
• The EGFET sensor was tested in various pH buffer solutions to measure its response.

Main Results:

• The PSi-based EGFET demonstrated a sensitivity of 66 mV/pH, exceeding the theoretical Nernstian limit.
• The sensor exhibited stable operation within a broad pH range (2-12).
• Hysteresis values were recorded as approximately 8.2 mV (low pH) and 10.5 mV (high pH).

Conclusions:

• Porous silicon is a promising material for developing highly sensitive and stable pH sensors.
• The PSi-based EGFET shows potential for accurate hydrogen ion detection in diverse solutions.
• Further research can explore optimizing PSi properties for advanced sensing applications.