Indu Sharma

Bio: Indu Sharma is an academic researcher from Guru Gobind Singh Indraprastha University. The author has contributed to research in topics: Surface modification & Vapours. The author has an hindex of 1, co-authored 1 publications receiving 8 citations.

Optical measurement of trace level water vapours using functionalized porous silicon: selectivity studies

Abstract: Selective detection of trace level water vapours by functionalized porous silicon (PS) using photoluminescence (PL) quenching technique is reported. This sensitive technique provides sensing data through optical probing on a surface with a submicron surface area. PS samples were prepared via electrochemical etching and were functionalized using ammonium sulphide and UV exposure which brought about major changes in the surface properties. Samples were examined using SEM, FTIR, contact angle and PL spectroscopy. These samples were tested as sensors in the presence of linear aliphatic alcohols and water vapours in the wide range of 0–400 ppm. An increasing trend of sensor response with increase in alcohol chain length and minimal response to water vapours was observed from sensors based on as-anodized PS samples whereas post functionalization, sensors portrayed an opposite response wherein selective response to water vapours and minimal response to alcohols was indicated. The role of surface nitridation is highlighted in selective sensing of water vapours. A correlation between the sensing response and surface chemistry of samples has been established. It is implicated that sensing is directly linked to both the chemical properties of the sensing surface and analytes. A highly sensitive sensor for detection of water vapours at low ppm is presented. A simple and compact design of portable optical sensors, applicable for water vapour sensing is proposed.

Wafer-Scale Synthesized MoS2/Porous Silicon Nanostructures for Efficient and Selective Ethanol Sensing at Room Temperature

Abstract: This paper presents the performance of a highly selective ethanol sensor based on MoS2-functionalized porous silicon (PSi) The uniqueness of the sensor includes its method of fabrication, wafer scalability, affinity for ethanol, and high sensitivity MoS2 nanoflakes (NFs) were synthesized by sulfurization of oxidized radio-frequency (RF)-sputtered Mo thin films The MoS2 NFs synthesis technique is superior in comparison to other methods, because it is chip-scalable and low in cost Interdigitated electrodes (IDEs) were used to record resistive measurements from MoS2/PSi sensors in the presence of volatile organic compound (VOC) and moisture at room temperature With the effect of MoS2 on PSi, an enhancement in sensitivity and a selective response for ethanol were observed, with a minimum detection limit of 1 ppm The ethanol sensitivity was found to increase by a factor of 5, in comparison to the single-layer counterpart levels This impressive response is explained on the basis of an analytical resistiv

Interfacial Engineering in TiO 2 /Nano-Si Heterostructure-Based Device Prototype for E-Nose Application

Abstract: This paper presents the selective and highly sensitive performance of porous TiO2/nano-Si heterostructure for ethanol sensing. The fabrication steps involved were scalable and reproducible making the device eligible for batch fabrication suitable for industry production. The sensor response was recorded as a change in resistance upon exposure to a variety of organic vapors in the concentration range of 5–500 ppm and in simulated real breath conditions. Although the response was obtained at room temperature, however, the operating temperature of the sensor was found to be around 100 °C. The sensing mechanism has been explained on the basis of adsorption–desorption theory of gases, physical, and chemical properties of the materials. A prototype was built for complete realization of the sensor. The sensor data from the sensor array comprising of hetersostructure and its single-layer counterparts were collated and signal conditioning like Regression model and PCA was done. These were used for assessing the alcohol concentration and separation of analytes for the development of E-nose system.