NANO SCALE POROUS SILICON MICROCAVITY OPTICAL SENSOR DEVICE FOR THE DETECTION OF METHYL PARATHION

Methyl Parathion (MP) is one of the pesticides used in the agriculture field for the protection of cotton trees against pests. In this paper, a novel technique for the detection of MP using simple and low cost one dimensional (1D) nano scale Porous Silicon (PS) Microcavity (MC) sensor device is reported. Sensor device was fabricated by electrochemical anodization of crystalline silicon wafer and proposed as a large surface area matrix for optical sensing of MP concentrations (in ppm) present in water and Humic Acid (HA) solutions. Wavelength shift (Delta lambda) in the measured reflectance spectra were analyzed for the detection of the MP in the porous structure. Sensor device showed excellent sensing ability and good linear relation between the different concentrations of MP and the wavelength shift. Also, it was observed that, the resonant wavelength in the reflectance spectra of the 1D-PSMC sensor device promptly returned to its original states after removal of MP liquid from the porous structure. This is a very good quality of these structures, as it is helpful in the development of reversible sensing devices.