Properties of thin ZnS:Mn films sprayed by improved method: The role of Mn²⁺ ion concentration

Abstract

Undoped and Mn-doped thin ZnS films were deposited on ordinary glass substrates at temperature of 450 °C by an improved spray pyrolysis (ISP) method. The ISP parameters, such as carrier gas flow rate, solution flow rate and substrate temperature, were controlled with accuracy ±0.25 Lpm, ±1 mL/h and ±1 °C, respectively. A pulse-spray mode of the method was used to spray the precursor solution. Thin film samples were prepared for Mn-doping with the concentrations of 0 at.%, 1 at.%, 3 at.%, 6 at.%, 8 at.% and 12 at.% relative to Zn in the spray solution. The Mn-doping concentration dependent chemical composition, surface morphology, and structural, optical and photoluminescence (PL) properties were studied. All the thin films were well adherent, nearly stoichiometric, dense, uniform, and possessed cubic crystal structure with preferential orientation along h〈1 1 1〉 direction. A slight enhancement in structural properties, an increase in band gap, and a decrease in refractive index and dielectric constant with Mn-doping concentration were observed. The PL spectra of Mn-doped thin ZnS films at room temperature exhibited both the 490 nm blue defect-related emission and the 590 nm yellow-orange Mn2+ ion related emission. The observed yellow-orange emission intensity was maximum for 3 at.% of Mn-doping concentration in the spray solution.

Band Gap Tailoring, Size Modulation and Photoluminescence Properties of Mn/Cu doped ZnS Nanostructures

“…The identical shift along higher diffraction angles was reported in Ni added ZnS nanostrucutres by Kaur et al [15] Figure 2b Mn and Cu dual doping. The slight increase of size in Mn-doped ZnS is due to replacement of Mn 2+ ions (ionic radius ∼ 0.80 Å) in the position of Zn 2+ (ionic radius ∼ 0.74 Å) [17]. The same kind of size increment is noticed by Wang et al [18] in Mn added ZnS.…”

Improved Photocatalytic Performance of Cobalt Doped ZnS Decorated with Graphene Nanostructures under UV-visible Light: Towards Efficient H2 Production

“…The XRD investigation suggested that the doping elements Cobalt may have been properly substituted into Zn-S lattice, as there were no secondary or impurity phases identified. The peak positions of the Cobalt doped samples significantly shift upward in the 2θ values indicates that Co 2+ (0.58 Å) has a smaller ionic radius compared to that of Zn 2+ (0.74 Å) in the ZnS [42][43][44]. Due to the ionic radius of Cobalt being slightly smaller (0.58 Å) than that of Zn, the peak positions of samples that contain Cobalt exhibit a little shift towards lower 2θ values.…”