Structural and electrical characterizations of nanocrystalline Zn1−xCdxS (0≤x≤0.9) prepared by low cost dip coating

• Published in: Materials science in semiconductor processing Vol. 24; pp. 169 - 178
• Main Authors: El-Wahidy, E.F., Farag, A.A.M., Rafea, M. Abdel, Roushdy, N., El-Shazly, O.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2014; Elsevier
• Subjects: Atomic force microscopy; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity phenomena in semiconductors and insulators; Cross-disciplinary physics: materials science; rheology; Electronic transport in condensed matter; Exact sciences and technology; Glasses (including metallic glasses); Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Mobility edges ; hopping transport; Nanocrystalline Zn1−xCdxS; One-dimensional variable range hopping; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; Space charge limited current; Specific materials; Atomic force microscopy; Space charge limited current; Nanocrystalline Zn1−xCdxS; One-dimensional variable range hopping; Cd; Space-charge-limited conduction; Electrical conductivity; Photoluminescence; Glass; Charge transport; XRD; SAED; Acetates; Hopping conduction; Thin films; Low voltage; S; Aqueous solutions; Thiourea; Dip coating; IV characteristic; Current density; Cost lowering; Nanocrystal; Electrical characteristic; Defect states; Cadmium; Electrical properties; Zinc; Nanocrystalline Zn; Three dimensional model; One dimensional model; Transport processes
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2014.02.028

Thin films of nanocrystalline Zn1−xCdxS (0≤x≤0.9) were deposited by a dip coating method on glass substrates from aqueous solution containing cadmium acetate, zinc acetate and thiourea at 200°C. The morphological, structural and electrical properties of the deposited Zn1−xCdxS thin films were studied by atomic force microscopy (AFM), X-ray diffractometer (XRD), selected area electron diffraction (SAED) and photoluminescence (PL). To understand the predominant conduction mechanism of the nanocrystalline Zn1−xCdxS (0≤x≤0.9) thin films, DC electrical conductivity was measured in the temperature range of 300–420K. These measurements revealed that the DC behavior of the films can be described by a one-dimensional variable range hopping (VRH) model in the entire temperature range instead of a three-dimensional variable range hopping (VRH) model. The current density–voltage (J–V) characteristics of Zn1−xCdxS (0≤x≤0.9) thin films shows that the current conduction is ohmic type at the low-voltage region while the charge transport phenomenon appears to be space charge limited current (SCLC) at the higher-voltage regions. The latter conduction is attributed to the presence of a discrete trapping level. Various electrical parameters were determined and studied as a function of Cd-content such as electron mobility (μ0), density of states in conduction band (Nc), Fermi energy (EF), trap energy (Et) and trap electron density (Nt).