Application of tungsten oxide thin film in the photonic crystal cavity for hydrogen sulfide gas sensing

Abstract In this work, we report the design and simulation of a high sensitivity hydrogen sulfide (H2S) gas sensor based on the Ln slot photonic crystal cavity. To improve the sensitivity of the sensor, a layer of tungsten oxide (WO3) is coated on the inner walls of the slot. Change in concentration of H2S varies the refractive index of WO3 and leads a more wavelength shift in the output transmittance spectrum of the sensor which increases the sensitivity. We showed that the proposed sensor possesses an ultra-high sensitivity up to 2.3× 105 nmRIU−1, and a high Q factor of 3 ×103.