L.A. Patil

Growth of CuBiS2 thin films by chemical bath deposition technique from an acidic bath

Abstract CuBiS2 thin films have been deposited on a glass substrate by chemical bath deposition (CBD) technique in an acidic medium. Films are deposited for various concentrations of copper and bismuth. The effect of deposition time and temperature on growth of these films have been studied. To obtain good quality films, the films are grown using a complexing agent. The disodium salt of [EDTA] is used as a complexing agent. The effect of deposition time, temperature and pH on growth of these films are reported. Optical, structural and electrical properties of these films are also reported.

Ammonia Sensing Resistors Based on

Thick films of ZnO were prepared by a screen printing technique. Unmodified ZnO thick film was almost insensitive to NH₃. ZnO thick films were surface modified with Fe³⁺ by dipping them into an aqueous solution of ammonium ferric sulfate for different intervals of time and fired at 500degC for 24 h. The ammonium ferric sulfate would transform into ferric oxide Fe₂O₃ upon firing. The grains of Fe₂O₃ dispersed around the grains of ZnO base material. Upon exposure to NH₃ gas, the barrier height Fe₂O₃-ZnO intergranular region decreases markedly due to the chemical transformation of Fe₂O ₃ into ammonium ferric hydroxide, leading to a drastic increase in conductance. The ZnO film dipped for 5 min (with 0.74 mass % of Fe₂O₃) was observed to be most sensitive to NH ₃ gas at 350degC. The Fe-surface misfits, calcination temperature, and operating temperature can affect the microstructure and gas sensing performance of the sensor. The efforts are made in present paper to develop the sensor using surface-modified zinc oxide. An exceptional sensitivity was found to low concentrations (50 ppm) of NH ₃ gas at 350degC, and no cross sensitivity was observed, even to high concentrations of other hazardous and polluting gases. The effects of microstructure and surfactant concentration on the sensitivity, selectivity, response, and recovery of the sensor in the presence of NH₃ gas were studied and discussed

{\rm Fe}_{2}{\rm O}_{3}

Purpose – The purpose of this paper is to show how to obtain better response, selectivity and fast response and recovery from nanocrystalline ZnO‐based gas sensors as compared to conventional materials.Design/methodology/approach – Nanocrystalline ZnO powders were prepared from the ultrasonic spray pyrolysis method. Aqueous solution of zinc acetate was atomized using ultrasonic atomizer. The aerosol generated was fed to the reaction furnace for pyrolysis. Nanocrystalline ZnO crystallites were collected using simple but novel trapping system. Thick film resistors of this powder were fabricated using screen printing technique.Findings – As‐prepared powder was studied using X‐ray diffraction, transmission electron microscopy and scanning electron microscopy to know structure, size of nanocrystallites and microtopography, respectively. Absorption spectroscopy is used to determine the band gap energy. The gas‐sensing performance of this film was tested.Originality/value – The sensor was found to be the most se...

-Modified ZnO Thick Films

Nanocrystalline zinc-oxide (ZnO) powders were prepared from the ultrasonic atomization method. An aqueous solution was atomized by using the ultrasonic atomizer operating at 2.1 to 2.3 MHz. The generated droplets were fed to the reaction furnace for pyrolysis. Nanocrystalline ZnO crystallites were collected by using a simple but novel trapping system, and prepared powder was characterized using X-ray diffractogram, transmission electron microscopy, scanning electron microscopy, and absorption spectroscopy. Nanostructured thick-film sensors of this powder were prepared by using the screen printing technique. The gas sensing performance of this film was tested. The sensor was found to be most sensitive to NH3. The results were discussed and interpreted.

Ultrasonically synthesized nanocrystalline ZnO powder‐based thick film sensor for ammonia sensing

In this paper, we report on the effect of concentration on nanocrystalline ZnO powder prepared by an ultrasonic atomization technique, which is a promising method because of its simplicity, inexpensiveness and safety. The morphology and size of ZnO nanocrystallites associated with nanopowder were characterized by transmission electron microscopy (TEM). It revealed that the powder consisted of nanocrystallites with grain sizes between 8 and 15 nm. These values match the grain sizes (8–14 nm) calculated from x-ray diffraction (XRD). The XRD and TEM studies of ZnO nanopowder showed that crystallite sizes were observed to increase with an increase in the concentration of solution. The d values calculated from electron diffraction patterns (TEM) of ZnO nanopowder were also in agreement with the d values calculated from XRD. The synthesized nanopowders exhibited a direct band gap (Eg) in the range of 3.36–3.42 eV.

Synthesis of ZnO Nanocrystalline Powder From Ultrasonic Atomization Technique, Characterization, and its Application in Gas Sensing

In this article, we report on the effect of pyrolysis temperature on structural, microstructural and optical properties of nanocrystalline ZnO powder synthesised by ultrasonic spray pyrolysis (USP) technique. Powder samples P1, P2 and P3 were prepared at various pyrolysis temperatures (temperature of 2nd zone) of 973, 1073 and 1273 K, respectively. Phases were identified and crystallite sizes were calculated from X-ray diffraction (XRD) diagrams. The morphology and size of ZnO nanocrystallites associated with nanopowder were studied using transmission electron micrograph (TEM). It revealed that the powder consisted of crystallites ranging in size from 9 to 20 nm. These values were matching with the crystallite sizes calculated from XRD. Both XRD and TEM studies of ZnO nanopowders showed that the crystallite sizes increased with an increase in the pyrolysis temperature. The synthesised nanopowders exhibited direct band gap (E g) in the range 3.37–3.40 eV.

Effect of precursor concentrations on structural, microstructural and optical properties of nanocrystalline ZnO powder synthesized by an ultrasonic atomization technique

CdSnO₃ thin films were prepared using ultrasonic spray pyrolysis technique. The structural, microstructural, and optical properties of the films were studied using X-ray diffraction, transmission electron microscopy, and UV-VIS spectroscopy, respectively. The sensing performance of a typical film was tested for chemical warfare agent simulants, such as, 2-chloroethyl ethyl sulfide C₄H₉ClS CEES (CEES), dimethyl methyl phosphonate C₃H₉O₃P (DMMP), and 2-chloroethyl phenyl sulfide C₈H₉ClS (CEPS). The simulant sensing performance of CdSnO₃ thin-film-based sensor was tested. CdSnO₃ thin-film-based sensor was observed to be more sensitive to CEES as compared with DMMP and CEPS. The results were discussed and interpreted.

Effect of pyrolysis temperature on structural, microstructural and optical properties of nanocrystalline ZnO powders synthesised by ultrasonic spray pyrolysis technique

Spray pyrolysis techniques was employed to prepare BaTiO3 thin films. AR grade solutions of Barium chloride (0.05 M) and Titanium chloride (0.05 M) were mixed in the proportion of 30:70, 50:50 and 70:30. The solutions were sprayed on quartz substrate heated at 350°C temperature to obtain the films. These thin films were annealed for a two hours at 600°C in air medium respectively. The prepared thin films were characterized using XRD, FESEM, EDAX, TEM. The electrical and gas sensing properties of these films were investigated. 50:50 film showed better response to Liquid Petroleum Gas (LPG) as compare 30:70 and 70:30 films.Spray pyrolysis techniques was employed to prepare BaTiO3 thin films. AR grade solutions of Barium chloride (0.05 M) and Titanium chloride (0.05 M) were mixed in the proportion of 30:70, 50:50 and 70:30. The solutions were sprayed on quartz substrate heated at 350°C temperature to obtain the films. These thin films were annealed for a two hours at 600°C in air medium respectively. The prepared thin films were characterized using XRD, FESEM, EDAX, TEM. The electrical and gas sensing properties of these films were investigated. 50:50 film showed better response to Liquid Petroleum Gas (LPG) as compare 30:70 and 70:30 films.