Light-optimized photovoltaic self-powered NO₂ gas sensing based on black silicon

The NO₂ sensing performance of a special lateral photovoltaic self-powered gas sensor based on the N-hyperdoped microstructured silicon (N-Si) is systematically studied under the different light illumination. The dependence of sensing characteristics on light intensity and wavelength is obtained, respectively. Results show that the sensing properties can be changed effectively by the different intensities and wavelengths, suggesting that a multidimensional regulation/optimization for the sensing characteristics is possible by light. More interestingly, the light with wavelength of 940 nm and intensity of ∼18 μW/cm² could bring a comprehensive optimization for gas sensing, under which the N-Si sensor exhibits the excellent overall performance with simultaneously the low light power needed, good gas response, high sensitivity, wide detectable range and short response time at room temperature.