Performance comparison of room temperature-operated mid-infrared

CO₂ gas sensing holds significant importance across various sectors including environmental monitoring, chemical industries, manufacturing processes, medical capnography and biomedical diagnostics. Two types of CO₂ sensors primarily used for gas sensing are electrochemical sensors and non-dispersive infrared (NDIR) sensors. Electrochemical sensors, despite their usage, suffer from poor long-term stability and cross-sensitivity to other gases. Therefore, NDIR gas sensors, which offer long-term reliability and high sensitivity, are particularly attractive in the CO₂ sensor market. These sensors rely on semiconductor materials with a high absorption coefficient around in the mid-infrared (mid-IR) wavelength range. Among the semiconductor materials suitable for cost-effective detector applications, PbSe and InAsSb are particularly noteworthy due to their demonstrated high operating temperature (HOT) capability. This study provides a comparison of the electrical, optical, and electro-optical characteristics of photovoltaic InAsSb and photoconductive PbSe detectors. Both types of detectors were found to operate effectively at room temperature, and their performance characteristics were evaluated, including temperature-dependent dark current, shunt resistance, and cryogenic Fourier-transform infrared (FTIR) spectral response from 77K to 340K. Additionally, key performance parameters such as 1/f noise, noise equivalent power (NEP), quantum efficiency, and specific detectivity (D*) were estimated and analyzed. This paper presents a detailed analysis of these characteristics for both types of detectors, as well as simulation results, providing valuable insights for practical applications in NDIR spectroscopy.