Absorption spectroscopy gas sensor using a low-cost quartz crystal tuning fork with an ultrathin iron doped cobaltous oxide coating

• DOI: 10.1016/j.snb.2020.128951
• Publication Date: 2020-09-25T13:37:11Z
• Authors: Sheng Zhou; Linguang Xu; Kui Chen; Lei Zhang; Benli Yu; Tongtong Jiang; Jingsong Li
• Keywords: Photoelectric effect; Crystal (programming language); Gas detector

Abstract A proof-of-concept photoelectric detector is proposed for use in low-cost, compact, and highly sensitive gas sensors. This detector is based on a quartz crystal tuning fork (QCTF) coated with an ultrathin two-dimensional (2D) iron doped cobaltous oxide (Fe-CoO) film. The Fe-CoO film enhances the photoelectric conversion efficiency of the detector. This detector is combined with wavelength modulation spectroscopy, and its suitability for trace gas sensing is demonstrated using CH4. A minimum detection limit of 0.88 ppmv is achieved with an integration time of 1 s. This corresponds to a normalized noise equivalent absorption coefficient of 2.2 × 10−10 cm-1·W Hz-1/2. Allan variance analysis is used to evaluate the stability of the proposed system, and the results show that an optimum precision of 20 ppbv can be achieved with an integration time of 220 s. Ultrathin 2D materials may be used to develop new photoelectric detectors that have an ultrawide wavelength response range and high photoelectric conversion efficiency. This would provide flexibility and chemical stability at low cost for applications in harsh environments.