http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/32 2026-04-24T12:44:30Z 2026-04-24T12:44:30Z Jasmi, K K Johny, T. Anto Siril, vs Madhusoodanan, K.N. http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/429 2025-01-30T09:30:58Z 2023-06-01T00:00:00Z

Influence of defect density states on NO2 gas sensing performance of Na: ZnO thin films Jasmi, K K; Johny, T. Anto; Siril, vs; Madhusoodanan, K.N. In this work, the Zn1-xNaxO (x = 0, 0.01, 0.03, and 0.05) thin film gas sensors were prepared via the sol-gel spin coating method to study the impact of sodium on structural, morphological, elemental, electrical, and gas sensing applications. Crystal structure (XRD), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), four-probe hall measurement, and NO2 gas sensing properties were investigated to ascertain the elemental composition, morphology, defect density states, working temperature, response/recovery time, stability, selectivity, and repeatability. The 3 wt.%Na:ZnO gas sensor displays a gas-accessible structure with more oxygen vacancies, remarkable stability, and sensitivity towards NO2 gas at an optimum temperature (210 °C). A possible gas-sensing mechanism was also discussed and correlated with structural, elemental, morphological, and electrical properties.

2023-06-01T00:00:00Z Jasmi, K K Johny, T. Anto Siril, vs Madhusoodanan, K.N. http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/428 2025-01-30T07:10:14Z 2023-10-01T00:00:00Z

Influence of oxygen vacancies on the lithium-doped Mn:ZnO thin films for improved NO2 gas-sensing applications Jasmi, K K; Johny, T. Anto; Siril, vs; Madhusoodanan, K.N. Herein, the (Zn0.97−xLixMn0.03)O ( x = 0, 0.01, 0.03, and 0.05 ) thin flms were prepared on a glass substrate via the sol–gel spin coating technique to study the infuence of lithium on Mn-doped ZnO thin flms for structural, optical, electrical, morphological, chemical, and NO2 gas-sensing applications. According to the XRD analysis, all samples display a hexagonal wurtite crystal structure. A FESEM analysis revealed that the incorporation of lithium into Mn-doped ZnO results in a smaller grain size with more voids than Mn-doped ZnO. Four-probe Hall measurements revealed the n-type conductivity on (Zn0.97−xLixMn0.03)O ( x = 0 and 0.01), whereas samples with ( x = 0.03 and 0.05 ) exhibited p-type conductivity, which was well explained. XPS and PL spectra confrmed the abundance of surface oxygen vacancies on the prepared sample. It is revealed that interaction between the defect states of lithium and manganese with inherent defect states of ZnO play a crucial role in carrier transfer for the gas-sensing process. In contrast to Mn-doped ZnO, (Zn0.96Li0.01Mn0.03)O exhibits smaller grains and a ninefold gas sensitivity (62.01) toward 75 ppm of NO2 gas at 210 °C toward 75 ppm of NO2 gas with a rapid response (30 s) and recovery (125 s) time

2023-10-01T00:00:00Z Jasmi, K K Johny, T. Anto Siril, vs Madhusoodanan, K.N. http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/427 2025-01-30T07:01:04Z 2023-05-01T00:00:00Z

Enhanced NO2 gas sensing performance of Gd/Li co-doped ZnO thin films Jasmi, K K; Johny, T. Anto; Siril, vs; Madhusoodanan, K.N. In this paper, we demonstrate pure, Gd-doped, and Gd/Li co-doped ZnO nanostructures for NO2 gas sensing applications fabricated via the sol–gel spin coating route. The synthesized samples are examined through various characterization techniques to evaluate their physical and chemical properties. The gas sensing performance of all deposited samples was investigated at different temperatures (150–240 C) towards 75 ppm of NO2 gas. Among them, the Gd/Li codoped ZnO sample shows remarkable NO2 gas sensing performance of 55.18 at a working temperature of 210 C. Also, the gas sensitivity of Gd/Li: ZnO towards various toxic gases, including Cl2, NH3, NO, and NO2, were studied and appeared most selective towards NO2 gas. A possible NO2 gas sensing mechanism was discussed and correlated with structural, morphological, electrical, and spectral studies

2023-05-01T00:00:00Z Jasmi, K K Johny, T. Anto Siril, v s Madhusoodanan, K.N. http://starc.stthomas.ac.in:8080/xmlui/xmlui/handle/123456789/398 2025-01-20T08:10:10Z 2023-08-31T00:00:00Z

Performance of alkali metal (Li/Na): ZnO thin films for NO2 gas sensing Jasmi, K K; Johny, T. Anto; Siril, v s; Madhusoodanan, K.N. Metal Oxide Semiconducting (MOS) gas sensors based on ZnO are extensively explored due to their exceptional physicochemical properties. Here, prepared films were characterized through XRD, FESEM, and Hall measurements to verify the physical as well as electrical properties. NO2 gas sensing performance of undoped and alkali-metal (Li/Na):ZnO films are evaluated. The operating temperature, sensitivity, and response/recovery time of prepared sensors towards nitrogen dioxide(NO2) were conducted. Through a comparative analysis of NO2 gas sensing activity of pure and 1 wt% of alkali metal (Li/Na) doped ZnO thin films. Lithium-doped ZnO sensors were found to exhibit higher sensitivity and rapid response/recovery time. Fabricated sensors detected NO2 test gas at 15 ppm, which is lower than the exposure limit (20 ppm). The gas sensing mechanism involving adsorption/desorption of the species on the surface of the sensor is also proposed.

2023-08-31T00:00:00Z