Macroporous Silicon Filters, a Versatile Platform for NDIR Spectroscopic Gas Sensing in the MIR

Abstract

This paper describes the spectroscopic detection of gases using macroporous silicon photonic crystals as narrow filters. The study begins by demonstrating the feasibility of photoelectrochemical etching to fabricate narrow filters along the mid infrared band. Next, we focus on the filter centered on the carbon dioxide fingerprint. The filter response is described for three different cell lengths and concentrations below 1%. Results show a concordance with the reformulated Beer-Lambert law. This can be used to predict the response of the filter for longer path lengths and higher concentrations, showing broad working ranges and compact sizes for CO 2. In addition, optical robustness to external variations and long-term stability are also reported. Results are extrapolated to other macroporous silicon filters centered on the absorption spectra of N 2 O, OCS, NO 2 and SO 2. Finally, high sensitivity and selectivity is demonstrated by comparing them with some commercial filters.

Low-cost porous silicon material based on fenton process assisted chemical etching and its application as anode for lithium-ion battery

“…However, these etching methods were originally designed for the field of microelectronics and are more suitable for silicon wafers. For example, anisotropic porous arrays formed by electrochemical etching are used for the preparation of photonic crystal devices [6]. On the other hand, MACE is a highly controllable and adaptable top-down chemical process, which can be applied to almost all forms of silicon materials (including wafers, powders and particles).…”

Optics of Macroporous Silicon with Through Pores

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Novel pyroelectric single crystals PIN-PMN-PT and their applications for NDIR gas detectors

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