CVD Grown Cuprous Oxide Thin Film Based High Performance Chemiresistive Ammonia Gas Sensors

Cuprous Oxide (Cu
₂
O) is an important p-type semiconductor. Several micro and nano-structures of Cu
₂
O have been employed in sensing oxidizing and reducing gases. However, for mass production of sensors, large-area Cu
₂
O films are needed, which hitherto was a challenge. In this work we report a chemiresistive gas sensor based on pure-phase Cu
₂
O (~90 nm thick), synthesized by chemical vapor deposition (CVD). At an operating temperature of 200°C, the sensor is highly-sensitive to ammonia. The device response varies from 0.81% to 5.21%, when exposed to ammonia with concentration of 300 ppb to 3 ppm. The response time (τ
_response
) and recovery time (τ
_recovery
) of the device were found to be decent for practical applications. Unlike competing techniques for Cu
₂
O deposition, Cu2O from chemical vapor deposition leads to sensors that are more repeatable, stable and reproducible.