Fabrication of a Graphene-Based Chemiresistor for Ammonia Gas Detection

Graphene-based gas sensors have various applications due to their strong electronic and mechanical properties that serves as an excellent material for gas sensing. This study investigates the fabrication, characterization, and application of a graphene-based chemiresistor for ammonia gas sensing. Graphene was grown on copper using the chemical vapor deposition (CVD) method. To make the chemiresistors, graphene was transferred onto interdigitated electrodes on a printed circuit board using a wet transfer process. Post transfer, the graphene layer was characterized using atomic force microscopy (AFM) and Raman spectroscopy. The results verified the monolayer thickness of the transferred graphene.<br/> <br/>To assess the sensor's performance, the chemiresistor was exposed to ammonia gas in an enclosed chamber at various concentrations while its resistance was monitored using a potentiostat. The change in resistance was measured from 4.5 kΩ before exposure and increased to 5.4 kΩ after exposure to ammonia for 500 seconds, reflecting a 0.9 kΩ resistance increase. This sensor demonstrated a significant change in resistance due to its interaction with ammonia, highlighting its potential as a gas sensor.