Ru-implanted WS2 nanosheet gas sensors to enhance sensing performance towards CO gas in self-heating mode

초록

Ru-implanted (low-dose: 2 x10(13) ions/cm(2) and high-dose: 2 x10(14) ions/cm(2)) p-type WS2 nanosheet (NS) gas sensors were investigated for CO gas sensing in self-heating mode. X-ray photoelectron spectroscopic analysis showed that the implanted Ru existed as Ru3+ (similar to 38 at%) and Ru4+ (similar to 62 at%). A decrease of the resistivity after Ru implantation was attributed to the substitution of W4+ with Ru3+. The enhanced sensor response of the Ruimplanted (2 x10(14) ions/cm(2)) WS2 was attributed to the enhanced adsorption of oxygen onto the sulfur vacancies after Ru ion implantation. Decoration of Au nanoparticles (NPs) onto this gas sensor not only led to an enhancement of the response to CO gas but also improved the selectivity and dynamics of the gas sensor. The related sensing mechanism was explained in terms of the catalytic effect of Au and the spillover effect. The optimized gas sensor showed good response to CO in the presence of humidity (R-g/R-a = 3 to 50 ppm CO at 60% relative humidity, where R-a is the resistance of the sensor in air and R-g is its resistance in the presence of the target gas).

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