ZnS/ZnO heterostructure semiconductor: A promising ionic liquid media approach without calcination

Document Type : Research Paper


Department of Chemistry, College of Basic Sciences, Yadegar-e-Imam Khomeini (RAH) Shahre Rey Branch, Islamic Azad University, Tehran, Iran


ZnS is a wide band gap semiconductor with excellent optical and electrical properties whose electronic structure can be modified with other semiconductors. In this study, ZnS and ZnS/ZnO heterostructure semiconductors were fabricated using the reaction between ZnCl2 and Na2S in the presence and absence of ethyl pyridinium iodide ionic liquid media via a reflux route without calcination. The as-prepared samples were characterized by XRD, FE-SEM, EDS, and DRS techniques. The main observations were the effects of ethyl pyridinium iodide on structural features, morphology, and band gap. The XRD patterns of ZnS represented peaks at 2θ = 8.8, 28.6, 32.9, 47.6, 56.4, 69.7, 76.9º of the blende structure. The crystalline nature of ZnS/ZnO at 29.05, 34.43, 47.51, 56.57, 69.06º and 31.80, 36.26, 47.51, 56.57, 62.85, 66.38, 67.90º is compatible with the standard pattern of ZnS blende and ZnO Zincite phases, respectively. The ZnS/ZnO heterostructure showed that the crystal truncated hexagonal had a thickness of about 90 nm. The rough hexagonal contained several layers, and the averaged elemental enrichment of Zn : S : O was 1 : 0.29 : 0.67. The synergistic effects of ZnS and ZnO promoted band-gap narrowing compared to the ZnS blende particles. So, in the ZnS and ZnS/ZnO cases, the band gap energy was 4.17, and 2.82 eV, respectively. The proposed ZnS/ZnO heterostructure composite has potential applications in semiconductors. The findings of this study opened new aspects of ZnO/ZnS heterostructure in terms of preparation, morphology, and band gap value.

Graphical Abstract

ZnS/ZnO heterostructure semiconductor: A promising ionic liquid media approach without calcination


  • The band gap narrowing of ZnS/ZnO was due to the formation of a heterostructure.
  • The hexagonal morphology of ZnS/ZnO had a thickness of about 90 nm.
  • The XRD peaks were assigned to ZnS blende and ZnO zincite structures. 


Main Subjects

[1] Torabi, A., & Staroverov, V.N. (2015). Band gap reduction in ZnO and ZnS by creating layered ZnO/ZnS heterostructures. J. Phys. Chem. Lett. 6(11) 2075-2080.
[2] Singh, M,. Goyal, M, & Devlal, K. (2018). Size and shape effects on the band gap of semiconductor compound nanomaterials. J. Taibah Univ. Sci. 12(4) 470-475.
[3] Duan, Y., Stinespring, C.D., & Chorpening, B. (2015). Electronic structures, bonding configurations, and band-gap-opening properties of graphene binding with low-concentration fluorine. ChemstryOpen, 4(5) 642-650.
[4] Schrier, J., Demchenko, D.O., Wang, L.W., & Alivisatos, A.P. (2007). Optical properties of ZnO/ZnS and ZnO/ZnTe heterostructures for photovoltaic applications. Nano Lett. 7(8) 2377-2382.
[5] Hart, J.N., & Allan, N.L. (2013). GaP-ZnS Solid solutions: Semiconductors for efficient visible light absorption and mission. Adv. Mater. 25(21) 2989-2993.
[6] Saha, S.,  Sarkar, S., Pal, S., & Sarkar, P. (2013). Tuning the energy levels of ZnO/ZnS core/shell nanowires to design an efficient nanowire-based dye-sensitized solar cell. J. Phys. Chem. C, 117(31) 15890-15900.
[7] Saha, S., & Sarkar, P. (2013). Electronic structure of ZnO/ZnS core/shell quantum dots. Chem. Phys. Lett. 555, 191-195.
[8] Gao, X.X., Wang, J., Yu, J.L., & Xu, H.B. (2015). Novel ZnO-ZnS nanowire arrays with heterostructures and enhanced photocatalytic properties. CrystEngComm, 17(33) 6328-6337.
[9] Li, B.X., Wang, Y.F., & Wu, Y.L. (2012). Flower-like ZnO/ZnS heterostructures: Facile synthesis, structural characterization and photocatalytic activity. Chin. J. Inorg. Chem. 28(2) 417-424.
[10] Ma, H., Han, J., Fu, Y., Song, Y., Yu, C., & Dong, X. (2011). Synthesis of visible light responsive ZnO–ZnS/C photocatalyst by simple carbothermal reduction. Appl. Catal. B-Environ. 102(3-4) 417-423.
[11] Gao, P., Wang, L., Wang, Y., Chen, Y., Wang, X., & Zhang, G. (2012). One-pot hydrothermal synthesis of heterostructured ZnO/ZnS nanorod arrays with high ethanol-sensing properties. Chem.-Eur. J. 18(15) 4681-4686.
[12] Yu, X.L., Ji, H.M., Wang, H.L., Sun, J., & Du, X.W. (2010). Synthesis and sensing properties of ZnO/ZnS nanocages. Nanoscale Res. Lett. 5, 644-648. 
[13] Huang, X., Willinger, M.-G., Fan, H., Xie, Z.-L., Wang, L., Klein-Hoffmann, A., Frank Girgsdies, F., Lee, C.-S., & Meng, X.-M. (2014). Single crystalline wurtzite ZnO/zinc blende ZnS coaxial heterojunctions and hollow zinc blende ZnS nanotubes: Synthesis, structural characterization, and optical properties. Nanoscale, 6(15) 8787-8795.
[14] Baranowska-Korczyc, A.,  Sobczak, K., Dłużewski, P., Reszka, A., Kowalski, B.J., Kłopotowski, Ł., Elbaum, D., & Fronc, K. (2015). Facile synthesis of core/shell ZnO/ZnS nanofibers by electrospinning and gas-phase sulfidation for biosensor applications. Phys. Chem. Chem. Phys. 17(37) 24029-24037.
[15] Neveux, L., Chiche, D., Bazer-Bachi, D., Favergeon, L., & Pijolat, M. (2012). New insight on the ZnO sulfidation reaction: Evidences for an outward growth process of the ZnS phase. J. Chem. Eng. 181-182, 508-515.
[16] Lonkar, S.P., Pillai, V.V., & Alhassan, S.M. (2018). Facile and scalable production of heterostructured ZnS-ZnO/Graphene nano-photocatalysts for environmental remediation. Sci. Rep. 8, 13401. 
Volume 8, Issue 2
November 2022
Pages 115-119
  • Receive Date: 31 March 2023
  • Revise Date: 06 May 2023
  • Accept Date: 10 May 2023
  • First Publish Date: 10 May 2023