Effect of (Sm, Co) co-doping on the structure and electrical conductivity of ZnO nanoparticles

Abstract

(Sm, Co) co-doped ZnO nanoparticles (Zn1−2xSmxCoxO), 0.00 ≤ x ≤ 0.06 , have been prepared by the co-precipitation technique. The effect of the dopant ions Sm3+ and Co2+ on the structural, morphological, and electrical conductivity of ZnO has been studied. XRD analysis shows the substitution of Zn2+ ions by the co-doping Sm3+ and Co2+ ions with the formation of secondary phases as Sm2O3 and Co3O4 upon 0.005 co-doping and above. Raman spectra showed the characteristic mode of the wurtzite structure of ZnO nanoparticles with a vibration assigned to the bound of Co with the donor defects at high doping level of (Sm, Co). The spherical morphology of pure ZnO is transformed into nanorods as the concentration of Sm3+ and Co2+ increases. From EDX spectra, it was shown that all samples exhibit an excellent compositional homogeneity that verifies the Sm and Co presence as real dopants in ZnO crystalline structure. FTIR spectra show one discrete peak at 417 cm−1 with another broad peak at 568 cm−1corresponding to Zn–O stretching, which confirms the formation of the wurtzite structure of the samples. Photoluminescence studies reveal the existence of minor defects in the co-doped samples. The study proposes the suitable use of the samples in the high-efficiency UV light-emitting devices due to the intense UV peaks compared with the lower visible peaks. The excitation dependent PL spectra demonstrated a redshift with increasing the excitation wavelength accounting for the distribution of energetic species in the ground state. The DC electrical conductivity is enhanced with (Sm, Co) co-doping of x = 0.1 due to the formation of thermally activated donor levels.

Effect of Al Concentration on Structural, Optical and Electrical Properties of (Gd, Al) Co-Doped ZnO and Its n-ZnO/p-Si (1 0 0) Heterojunction Structures Prepared via Co-Sputtering Method

“…The dislocation density increased with the increase in Al concentration, which shows that there were more defects in the lattice with higher Al concentrations. Almoussawi et al reported that degradation of crystallinity at a higher amount of co-doping leads to an increase in dislocation density [ 25 ]. Thus, the decrease of film crystallinity with higher co-doping concentrations is associated with the increase in dislocation density.…”

The effect of Mn and Co dual-doping on the structural, optical, dielectric and magnetic properties of ZnO nanostructures

“…Peak appeared around 331 and 380 cm −1 is created due to multi phonon mode of E 2 (high)– E 2 (low) and A1(TO) respectively, which can be attributed to the single-crystalline nature of ZnO. 28 The intensities of these peaks decrease with doping, indicating that the inclusion of Mn/Co in the lattice may induce disorder in the system. A weak absorption peak at 580 cm −1 corresponds to E 1 (LO) mode of vibration which is created due to oxygen vacancies.…”

Detailed investigation of the structural and electrical properties of ZnO/Fe3O4 nanocomposites

“…The average dislocation density was found to be 10.6 × 10 −4 to 29.1 × 10 −4 nm −2 as shown in figure 2(b). The purity of the formed nanoparticles/nanocomposites phase with the formula (1-x)ZnO+xFe 3 O 4 was examined using Rietveld refinement analysis of the XRD data using the MAUD program, as shown in Figure 2(c) [30]. Figure 2.c shows the refinement results discovered the presence of ZnO and Fe 3 O 4 without any other phases in nanocomposites.…”