High-performance PANI sensor on silicon nanowire arrays for sub-ppb NH₃ detection.

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Real-time detection of low ammonia (NH3) concentrations is vital for industrial processes and disease diagnostics.
• Existing sensors often lack the sensitivity, selectivity, or integration compatibility required for advanced applications.

Purpose of the Study:

• To fabricate and characterize a novel NH3 gas sensor with enhanced sensitivity and a low limit of detection (LOD).
• To investigate the sensor's performance, including selectivity, reliability, and operational stability.

Main Methods:

• Fabrication involved wet etching and in-situ polymerization on silicon nanowire substrates to grow polyaniline fibers.
• Created sensors feature a p-p heterojunction and a three-dimensional network structure.
• Characterization and gas sensing performance tests were conducted to evaluate sensor capabilities.

Main Results:

• The fabricated NH3 sensor demonstrated exceptional detection capabilities, responding to concentrations as low as 1 ppb.
• Achieved LOD is one to two orders of magnitude lower than comparable commercial sensors.
• Verified selectivity and long-term reliability were observed, attributed to the silicon nanowire's high surface area and p-p heterojunction synergy.

Conclusions:

• The developed silicon-based gas sensor offers high sensitivity and ultra-low detection limits for NH3.
• The sensor's design is suitable for commercial integrated monitoring systems, providing stable and reliable gas detection.
• This work provides a reference for designing advanced silicon-based gas sensors with extended operational lifetimes.