Photoelectrochemical and Raman characterization of nanocrystalline CdS grown on ZnO by successive ionic layer adsorption and reaction method

• Published in: Thin solid films Vol. 562; pp. 56 - 62
• Main Authors: Kozytskiy, A.V., Stroyuk, O.L., Kuchmiy, S.Ya, Mazanik, A.V., Poznyak, S.K., Streltsov, Е.А., Kulak, A.I., Korolik, O.V., Dzhagan, V.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2014; Elsevier
• Subjects: Cadmium sulfide; Cadmium sulfides; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Electrodeposition, electroplating; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Methods of nanofabrication; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Phonon confinement; Phonons; Photocurrent; Photocurrent spectroscopy; Photoelectric effect; Physics; Quantum size effects; Raman spectroscopy; Solid surfaces and solid-solid interfaces; Surface chemistry; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Zinc oxide; Photocurrent spectroscopy; Zinc oxide; Phonon confinement; Cadmium sulfide; Raman spectroscopy; Quantum size effects; Raman spectra; Confinement; Quantization; Nanostructures; Quantum size effect; Thin films; Nanoparticles; Energy gap; Electrodeposition; Electrodeposited coatings; Nanocrystal; Nanomaterial synthesis; Photoexcitation; Electronic properties; Interband transitions; Light scattering; Photocurrents; Crystallinity; Adsorption; Ultraviolet visible spectrum; Phonon scattering; Photoconductivity; Nanostructured materials; Surface phonons; Heterostructures
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2014.03.070

Properties of CdS nanoparticles (NPs) grown by successive ionic layer adsorption and reaction (SILAR) method on the surface of electrodeposited ZnO films were studied by Raman, photocurrent and UV–Vis absorption spectroscopies. The CdS nanoparticles deposited at a SILAR cycle number (N) from 5 to 10 exhibit a broadening of the band gap (Eg) by 0.17–0.31eV as compared with that of the CdS particles grown at N=30. The size quantization of the interband transition energy in CdS nanoparticles is in accordance with the Raman spectroscopic data demonstrating a considerable increase in the LO peak intensity with increasing the N from 5 to 10 as a result of transition to resonant light scattering. The spectral width of the LO peak decreases from 50 to 15cm−1 as the N increases from 5 to 30 reflecting a less pronounced effect of the nanoparticle surface on the phonon scattering. A large spectral width of the Raman peaks is assumed to originate from a complex structure of the CdS nanoparticles comprising crystallinity domains that can affect the phonon confinement. The photocurrent spectroscopy of ZnO/CdS heterostructures showed that the band gap of CdS NPs deposited at N>20 is smaller by ~0.08eV than that of bulk cadmium sulfide. It was concluded that this effect is not associated with photoexcitation of structural defects but rather reflects intrinsic electronic properties of SILAR-deposited CdS nanoparticles. •Visible-light-sensitive ZnO/CdS heterostructures were prepared by SILAR.•A large Raman peak width originates from a complex structure of CdS nanoparticles.•Vibrational properties of CdS nanoparticles depend on SILAR cycle number.