The fabrication of reliable and cost‐effective gas sensor for low concentrations of toxic gases such as ammonia is still a challenging task, in this work the authors report structural, topography, and optical properties of pure and Ba‐doped Mn3O4 thin films prepared by chemical spray pyrolysis (CSP) as well as its gas sensing performance toward low concentrations of ammonia gas. XRD analyses prove the films have tetragonal spinel structure with a preferred orientation along the direction (103). AFM and SEM measurements show the films have homogeneous with rough surfaces and porous structures. EDS measurement confirms the presence of Mn, O, and Ba elements according to a doping concentration ratio. Optical measurements show the optical band gap redshifts and the bond length expands as Ba concentration increases. The optimal results are achieved in Mn3O4:Ba1% thin films where porous structure, rough surface, high crystallinity, and maximum response toward (20, 30, 40, and 50 ppm) of ammonia gas with great stability. Empirical equations are suggested to evaluate the sensitivity in terms of relative bond length and RMS roughness. These results show the films are good candidates in p‐type MOS gas sensors.
In2O3 thin films were grown by the chemical spray pyrolysis (CSP) method using the pneumatic spray set-up and compressed air as a carrier gas. Aqueous solutions containing InCl3.4H2O were deposited onto preheated glass sheets at substrate temperatures Ts=423-573K. X-ray differection (XRD) analysis confirmed the cubic bixbyite structure of indium oxide. The preferred growth orientation along the (211) plane for thin films. The crystallite size extracted from the XRD data corroborates the changes in full width at half maximum due to the variation in substrate temperature. It was shown that grain size of In2O3 thin film was (30)nm. Optical properties of In2O3 was studies and showed that the optical parameters (n, k α) were affected by substrate temperature.
The spectral properties of liquid and matrix sample of Rhodamine 6G (R6G) were evaluated. The acetone a used as a solvent and epoxy as host. The study for different concentration (5*10-6, 1*10-5, 5*10-5, 1*10-4 and 5*10-4 M/L) show that the absorption peak be will agree with Beer-Lambert law. And there is a blue shift the absorption curves and red shift in fluorescence curves with the concentration increase. The quantum efficiency for liquid were larger than the solid matrix. Also, the stock shift increases the concentration in both liquid and solid samples.
Cadmium sulfide (CdS) thin films were created using the pulse laser ablation technique and were applied to glass using varying pressure of argon gas (10, 20, and 30 torr). Characterized by X-ray diffraction and (scanning electron microscopy (SEM) and atomic force microscopy (AFM)) were studyed, additionally with various Ar gas pressures onelectrical characteristics are studied. The polycrystalline hexagonal structure of CdS films is demonstrated by X-ray diffraction analysis. To calculate the grain size of partical of deposited films which found the grain size ranges from (34-80) nm. Surface morphology measured using AFM give a spherical like structure and the average roughness was in the range of (6.45-11.49 nm).
The electrical measurement shows that the electrical conductivity of preoared films was from (5.9×10–4 ) to (13.8 × 10–4) (Ω cm)-1. From Hall measurements the deposited films show n-type conductivity. In order to make the CdS/Si junction a viable option for creating an effective photodiode.
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