Mesoporous Silicon Layer as a Highly Sensitive Ethanol Sensor

Mesoporous silicon (PSi) layer was used to create highly sensitive, electrically-based sensor for detection of liquid ethanol at room temperature. The PSi nanostructure that is generated in an electrochemical etching of crystalline silicon in HF-based solution was approximate to 4.5 mu m thick with an average pore size of 30 nm. The as-fabricated sensor exhibits highly sensitive, reversible response during the real-time measurements of capacitance and conductance. Excellent repeatability of the devise was obtained after six cyclic tests, demonstrating stability of the sensor. Long-term stability for the sensor performance was also observed after four weeks storage. The observed response could be understood in terms of the change in surface charge upon ethanol infiltration into the mesoporous structure.