“…Generally, the particles size, structural and optical properties of ZnS nanopowders were found to be sensitively dependent on the annealing temperature. Similar variations in E G was also observed on other nanoparticle systems such as ZnSe thin films 29 , ZnO nanorods 37 and ZnS doped Au, Mn and Ga 38 . Figure 7 The optical band gap ( E G ) and particles size ( P ) calculated from E G for non-annealed and annealed ZnS QDs.…”
Section: Resultssupporting
confidence: 82%
“…However, E G decreased with increasing annealing temperature. The decrease in E G may be attributed to the increase in particles size and decrease in the strain 29 . The data of E G and D presented in this study were compared to the previous works with various synthesis methods as shown in Table 3 25 , 30 – 36 .…”
ZnS quantum dots (QDs) were fabricated using the co-precipitation technique with no capping agent. The effects of different annealing temperatures (non-annealed, 240 °C and 340 °C for 2 h) on the structural and optical characteristics of ZnS QDs are reported. The samples were examined by XRD, TEM, PL, FTIR, and UV–Vis. An increase in annealing temperature led to an increase in the dot size and a lowering of the energy band gap (EG). The average crystallite size, D of ZnS was between 4.4 and 5.6 nm. The ZnS QDs showed a band gap of 3.75, 3.74 and 3.72 eV for non-annealed, 240 °C, and 340 °C annealed samples. The reflection spectra increased in the visible light and decreased in UV region with an increase in annealing temperature. This work showed that the band gap and size of ZnS QDs could be tuned by varying the annealing temperature.
“…Generally, the particles size, structural and optical properties of ZnS nanopowders were found to be sensitively dependent on the annealing temperature. Similar variations in E G was also observed on other nanoparticle systems such as ZnSe thin films 29 , ZnO nanorods 37 and ZnS doped Au, Mn and Ga 38 . Figure 7 The optical band gap ( E G ) and particles size ( P ) calculated from E G for non-annealed and annealed ZnS QDs.…”
Section: Resultssupporting
confidence: 82%
“…However, E G decreased with increasing annealing temperature. The decrease in E G may be attributed to the increase in particles size and decrease in the strain 29 . The data of E G and D presented in this study were compared to the previous works with various synthesis methods as shown in Table 3 25 , 30 – 36 .…”
ZnS quantum dots (QDs) were fabricated using the co-precipitation technique with no capping agent. The effects of different annealing temperatures (non-annealed, 240 °C and 340 °C for 2 h) on the structural and optical characteristics of ZnS QDs are reported. The samples were examined by XRD, TEM, PL, FTIR, and UV–Vis. An increase in annealing temperature led to an increase in the dot size and a lowering of the energy band gap (EG). The average crystallite size, D of ZnS was between 4.4 and 5.6 nm. The ZnS QDs showed a band gap of 3.75, 3.74 and 3.72 eV for non-annealed, 240 °C, and 340 °C annealed samples. The reflection spectra increased in the visible light and decreased in UV region with an increase in annealing temperature. This work showed that the band gap and size of ZnS QDs could be tuned by varying the annealing temperature.
“…The E G values are listed in Table 3 and confirmed that E G decreases with increasing annealing temperature. This decrease of energy band gap is likely to be due to decreases in strain values and increase of particle size that was confirmed by the XRD measurements [48,64,65]. On the other hand, the decrease of the optical band gap with the increasing annealing temperature is believed to originate from lattice expansion.…”
Ge15Se75Zn10 thin films were deposited onto cleaned glass substrates by the
vacuum thermal evaporation technique. The as-deposited and annealed thin
films were characterized by scanning electron microscopy, X-ray diffraction
and optical spectroscopy. The average particle sizes of the crystallized
GeSe and ZnSe phases increase with increasing annealing temperature. Some
optical parameters of the as-deposited and annealed Ge15Se75Zn10 thin films
were studied using both transmittance T(?) and reflectance R(?)
measurements. The analysis of T(?) and R(?) data revealed the existence of
direct optical band gap (EG) and the corresponding values were calculated to
be 2.913, 2.802 and 2.692 eV for the as-deposited and annealed thin films at
373 and 423 K, respectively. The dispersion of the refractive index is
discussed in terms of the single oscillator Wemple-Didomenico (WD) model.
The width of band tails of localized states (Ee), the single oscillator
energy (E0), the dispersion energy (Ed), the high frequency dielectric
constant (?L) and the steepness parameter (S) were estimated.
“…Data samples from forty-three compounds of doped zinc selenide nanostructured semiconducting materials were employed in developing SVR-GA and SPR models for energy gap quantification. The data samples were extracted from different sources in the literature [4,5,7,8,[33][34][35][36][37][38]. The descriptors such as the lattice parameter and the size of the semiconducting compounds were also extracted from the same sources with their corresponding energy gaps.…”
Section: Data Acquisition Description and Statistical Analysismentioning
confidence: 99%
“…The synthesis and characterization of zinc selenide semiconductor nano-materials has attracted global attention lately due to the novel properties demonstrated by zinc selenide semiconductors compared to other members of chalcogenide groups [1][2][3]. The features contributing to the uniqueness of this class of semiconductors include the lower electrical resistivity, non-toxicity, high transmission, insignificant lattice mismatching, wide energy band gap, as well as tunable light harvesting capacity over a range of spectrums [4]. These characteristic features, coupled with the quantum confinement effect, have enhanced and strengthened the practical application of zinc selenide semiconductors in various optoelectronics and photovoltaic applications, such as the thin-film winder layer of solar cells, thin-film transistors, ultrasonic transducers, small integrated circuits, anti-reflection coating, energy generation, laser screens, light-emitting devices, and catalysis [5][6][7].…”
Zinc selenide (ZnSe) nanomaterial is a binary semiconducting material with unique features, such as high chemical stability, high photosensitivity, low cost, great excitation binding energy, non-toxicity, and a tunable direct wide band gap. These characteristics contribute significantly to its wide usage as sensors, optical filters, photo-catalysts, optical recording materials, and photovoltaics, among others. The light energy harvesting capacity of this material can be enhanced and tailored to meet the required application demand through band gap tuning with compositional modulation, which influences the nano-structural size, as well as the crystal distortion of the semiconductor. This present work provides novel ways whereby the wide energy band gap of zinc selenide can be effectively modulated and tuned for light energy harvesting capacity enhancement by hybridizing a support vector regression algorithm (SVR) with a genetic algorithm (GA) for parameter combinatory optimization. The effectiveness of the SVR-GA model is compared with the stepwise regression (SPR)-based model using several performance evaluation metrics. The developed SVR-GA model outperforms the SPR model using the root mean square error metric, with a performance improvement of 33.68%, while a similar performance superiority is demonstrated by the SVR-GA model over the SPR using other performance metrics. The intelligent zinc selenide energy band gap modulation proposed in this work will facilitate the fabrication of zinc selenide-based sensors with enhanced light energy harvesting capacity at a reduced cost, with the circumvention of experimental stress.
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