Due to its unique transport properties, high surface-to-volume ratio and low electrical noise, graphene is highly sought after for high sensitivity detection of gases. A notable example is ammonia which has garnered increased research interest due to its usefulness in the early detection of kidney ailments via non-invasive techniques. However, graphene sensors for ammonia with ppb sensitivity have generally relied on the chemical modification of graphene thereby changing its carrier properties to induce faster and low concentration detection. While this has resulted in improved gas sensitivity towards ammonia, it is expected to also alter some of the unique properties of graphene such as its mobility, and the recovery time for the sensor. Recently, we showed using density functional theory calculations that the charge transfer characteristics, van der Waals interactions and the gas adsorption characteristics in various graphene-gas systems including (ammonia) can be modulated by applied gate voltage.
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