Recent status of chemical bath deposited metal chalcogenide and metal oxide thin films

Crystal structures, optoelectronic properties, and electronic structures of layered oxychalcogenides BiCuOCh (Ch = S, Se, Te) have been compared to those of LaCuOCh, with an emphasis on the electronic configurations of Bi3+ (5d106s2) and La3+ (5d06s0). The BiCuOCh series were expected to exhibit better hole-transport properties than the LaCuOCh series because the pseudo-closed-shell 6s2 electronic configuration of the Bi3+ cation was expected to form valence band maxima (VBM) by admixing with the p orbitals of the Ch anions. However, the two series of compounds exhibited similar electrical properties, suggesting that the contribution of the Bi 6s orbitals to the VBM is small in BiCuOCh. The crystal structures and optical properties showed distinct differences; for example, the band gaps of BiCuOCh were smaller than those of LaCuOCh. These findings can be understood on the basis of the electronic structures obtained by photoelectron spectroscopy and density functional theory calculations. The Bi 6s orbital...

Crystal Structures, Optoelectronic Properties, and Electronic Structures of Layered Oxychalcogenides MCuOCh (M = Bi, La; Ch = S, Se, Te): Effects of Electronic Configurations of M3+ Ions

Structure, microstructure and photoluminescence properties of Fe doped SnO2 thin films

Nanocrystalline lead selenide (PbSe) thin films were prepared on glass substrates by a chemical bath deposition method, using sodium selenosulfate (Na2SeSO3) as a source of Se2− ions, and lead acetate as a source of Pb2+ ions. Trisodium citrate (TSC) was used as a complexing agent. PbSe films were prepared at various deposition temperatures while the pH value was kept fixed at 11, and the effect on the resulting film properties was studied by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and optical absorption studies. The structural parameters, such as the lattice constant (a), crystallite size (D), dislocation density (ρ) and microstrain (e) were evaluated from the XRD spectra. It was found that average crystallite size, as calculated from Scherrer’s formula, increased from 23 to 33 nm as the deposition temperature was varied from 303 to 343 K. The dislocation density and microstrain were found to vary inversely with the crystallite size, whereas the lattice constant was found to increase with an increase in crystallite size. The optical absorption spectra of the nanocrystalline PbSe films showed a blue shift, and the optical band gap (Eg) was found to increase from 1.96 to 2.10 eV with the decrease in crystallite size.

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Effect of deposition temperature on the structural and optical properties of chemically prepared nanocrystalline lead selenide thin films.

Band gap engineering in PbS nanostructured thin films from near-infrared down to visible range by in situ Cd-doping

The optical band gap (Eg) of Pb1−xFexS solution-grown nanoparticle films was varied from 2.65 to 2.22 eV with an increase in iron concentration 0.25 ≤ x ≤ 0.75 in films grown at fixed pH and temperature by the chemical bath deposition method. The presence of excitonic structure in the ternary Pb1−xFexS for x ≥ 0.50 suggests increasing binding energy with increase in iron concentration in the films. A shift of excitonic peak towards higher energy with an increase in iron concentration is also observed.

https://iopscience.iop.org/article/10.1088/0957-4484/14/7/320/pdf

Size dependence of optical properties in solution-grown Pb1?xFexS nanoparticle films

Structural, optical and electrical properties of chemically grown Pb1−xFexSe nanoparticle thin films

Nanoparticle films of ternary Pb1?xFexS alloys were grown on glass and quartz substrates using a chemical bath deposition technique. Critical control of pH, temperature and dilution of the chemical bath was necessary for growth of the nanoparticle films. The ternary films were observed to grow as single phase with a lattice identical to that of PbS. Analysis of temperature-dependent dc conductivity data suggests variable-range hopping to be the conduction mechanism. Room-temperature Hall mobility of the films is found to increase with an increase in x and has a temperature dependence of ? T?0.4, which suggests predominant surface scattering. Majority carriers were found to be holes in the 0.25 ? x ? 0.50 films and electrons in the x = 0.66 and 0.75 films.

Structure, conductivity and Hall effect study of solution grown Pb1−xFexS nanoparticle films

PbSe nanocrystalline thin films have been prepared on glass and quartz substrates by chemical bath deposition method, using sodium selenosulfate, which acts both as a source of Se 2- ions and a complexing agent, in the chemical bath Effect of pH and temperature variation of the bath on grain size in the films is investigated; it is observed that the grain size increases with increase in pH and temperature The films grow with typical rock salt structure of PbSe and the lattice parameter shows a slight increase with decrease in the grain size Morphology of the grains is observed to be sensitive to their size While the smaller grains are spherical, the larger nanoparticles appear to gradually transform from spherical to square platelets and cubes Optical bandgaps (Eg) in the nanocrystalline films increase with decrease in grain size and have values larger than 028 eV of bulk PbSe The observed blueshift in the films is expected to originate from quantum confinement in the nanograins

Chemically Deposited PbSe Nanoparticle Films Variation in Shape and Size

Single-phase Pb 1-x Mn x S (0.03 ≤ x ≤ 0.37) nanoparticle films were prepared using an electroless solution growth technique. Face centered cubic structure with a decrease of lattice parameter for an increase of x in the alloy films was observed. Composition dependence of optical and electrical properties is discussed. The optical bandgap (E g ) could be varied from 1.50 to 2.50 eV by changing the x in the range 0.03 ≤ x ≤ 0.37 for the films. Effect of the grain size and the effect of alloying on optical properties are distinguished for the ternary nanoparticle films. Variable range hopping has been identified as mechanism for conduction in the p-type semiconductor Pb 1-x Mn x S nanoparticle films. Mobility (μ of the majority carriers shows a decrease with increase in Mn concentration x and follows a T -0.4 temperature dependence, indicating the surface scattering of carriers in the nanoparticle films.

H K Sehgal

Papers

Size dependence of optical properties in solution-grown Pb1?xFexS nanoparticle films

Structural, optical and electrical properties of chemically grown Pb1−xFexSe nanoparticle thin films

Structure, conductivity and Hall effect study of solution grown Pb1−xFexS nanoparticle films

Chemically Deposited PbSe Nanoparticle Films Variation in Shape and Size

Study of Solution Grown Variable BandGap Pb1 − x Mn x S Semiconductor Nanoparticle Films