Aqueous Phase Synthesis and Enhanced Field Emission Properties of ZnO-Sulfide Heterojunction Nanowires

Abstract

ZnO-CdS, ZnO-ZnS, and ZnO-Ag2S core-shell heterojunction structures were fabricated using low-temperature, facile and simple aqueous solution approaches. The polycrystalline sulfide shells effectively enhance the field emission (FE) properties of ZnO nanowires arrays (NWAs). This results from the formation of the staggered gap heterointerface (ZnO-sulfide) which could lead to an energy well at the interfaces. Hence, electrons can be collected when an electric field is applied. It is observed that ZnO-ZnS NWAs have the lowest turn-on field (3.0 Vμm−1), compared with ZnO-CdS NWAs (6.3 Vμm−1) and ZnO-Ag2S NWAs (5.0 Vμm−1). This may be associated with the pyramid-like ZnS shell which increases the number of emission nanotips. Moreover, the Fowler-Nordheim (F-N) plot displays a nonlinear relationship in the low and high electric field regions caused by the double well potential effect of the heterojunction structures.

Extended Short-Wavelength Infrared Photoluminescence and Photocurrent of Nonstoichiometric Silver Telluride Colloidal Nanocrystals

“…The two peaks correspond to the sulfur atom coordinated with silver in the Ag 2 S shell. 32,33 Interestingly, for the Ag 3.7 Te CQDs, the XPS spectrum shows three peaks at 161.7, 163.0, and 168.7 eV (Figures 3E and S10). The three S 2p peaks are consistent with the binding energies of the Ag−S and SO x .…”

Nitrogen-Doped Carbon for Sodium-Ion Battery Anode by Self-Etching and Graphitization of Bimetallic MOF-Based Composite

“…Some black nanoparticles were observed in the composite nanofibers after heating at 500 C (Figures 2D and 2G). High-resolution TEM (HRTEM) analysis of these particles (inset of Figure 2G) demonstrated that they have an interplanar distance of 0.26 nm, corresponding well to that of the ZnO (002) plane, 41 indicating that the Zn(Ac) 2 was converted into ZnO nanoparticles during the heating process. These ZnO nanoparticles are only localized in the fiber core, because of the initial distribution of O. TEM and EDX mapping further prove that ZnO/carbon composite nanofibers can be achieved by calcination of PAN/Zn(Ac) 2 /Co(Ac) 2 composite nanofibers in inert gas at 500 C (Figure S3).…”

Spontaneous Formation of a Hybrid Heterotrimer of Fe3O4-Ag2S-ZnS by Seeded-Growth Method

“…Zn, Ag and S. It should be noted here that in the high resolution spectrum Zn, Ag and S (Figure 6c) contain doublet features which were assigned to Zn 2p 3/2 , Zn 2p 1/2 , Ag 3d 3/2 , Ag 3d 5/2 , S 2p ½ and S 2p 3/2 respectively. [24,25] Additionally, the XPS spectrum of Zn 2p, Ag 3d and S 2p confirms their +2, +1 and -2 oxidation states respectively. Since the binding energy difference of these doublets matches well with the standard values, supporting the correct fitting and assignment of XPS peaks.…”