Resistivity, photoresistivity and magnetoresistance in sharp zincblende-wurtzite phase transition in CdS nanoparticles. (November 2017)

• Record Type: Journal Article
• Authors: Marquez-Marín, J.; Torres-Castanedo, C.G.; Torres-Delgado, G.; Castanedo-Pérez, R.; Zelaya-Ángel, O.
• Is Part Of: Superlattices and microstructures. Volume 111(2017)
• Page Start: 1217
• Page End: 1225
• Publication Date: 2017-11
• Subjects: Cadmium sulfide -- Nanoparticless -- Phase transformation -- Electrical properties; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2017.08.021
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: Cadmium sulfide nanoparticles were deposited by microwaves assisted chemical bath synthesis on glass substrates at bath temperatures (Tb ) in the range 60 ≤ Tb ≤ 97 °C. The films are formed of nanocrystals with a size of 6–20 nm. The crystalline phase depends on Tb, for 60 °C ≤ Tb ≤ 93 °C the lattice is cubic zinc blende and for Tb ≥ 95 °C hexagonal wurtzite. The critical temperature of phase transition is Tbc = 94 °C. Interplanar spacing calculated values, along the preferred orientation of growth, indicate that the lattice experiences a uniaxial contraction in the vicinity of Tbc, which is reflected in the thickness of the films. In this work, the electrical properties of these films are discussed and correlated with their structural ones for the whole temperature range. The electrical resistivity decreases as the nanoparticle size increases. Majority carrier density, mobility, and magnetoresistance experience strong variations around Tbc, similar to the behavior of the film thickness. As well as, resistivity measurements as function of (1/kT) show a change in the activation energy at Tbc . Highlights: Important changes on electrical properties of CdS nanoparticles in ZB→W phase transition. Resistivity decreases from 10 6 to 10 2 Ω -cm in sharp ZB→W phase transition in CdS nanoparticles. Negative magnetoresistance of −100 at RT, in CdS nanoparticulate films deposited by CB at Tb > 90 °C. Uniaxial internal stress in CdS nanoparticles by zinc blende-wurtzite transition.