Very sharp zinc blende-wurtzite phase transition of CdS nanoparticles. (February 2017)

• Record Type: Journal Article
• Authors: Márquez-Marín, J.; Torres-Castanedo, C.G.; Torres-Delgado, G.; Aguilar-Frutis, M.A.; Castanedo-Pérez, R.; Zelaya-Ángel, O.
• Is Part Of: Superlattices and microstructures. Volume 102(2017)
• Page Start: 442
• Page End: 450
• Publication Date: 2017-02
• Subjects: Cadmium sulfide -- Nanoparticles -- Phase transformation -- Optical properties -- Raman spectroscopy; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2017.01.007
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: Cadmium sulfide nanoparticles, in the size range of 6–20 nm, were prepared on glass substrates in the growth temperature (Tb ) interval of 60–97 °C by microwaves assisted chemical bath synthesis. The nanoparticle size was controlled by the bath temperature. The crystalline phase, shown in the X ray diffraction patterns, depends on the Tb range. In the intervals 60≤ Tb ≤ 93 °C and 95≤ Tb ≤ 97 °C the lattice is cubic zinc-blende (ZB) and hexagonal wurtzite (W), respectively. In Tb = 94 °C, the critical temperature of transition (Tbc ), the films have crystals in both cubic and hexagonal phases. The films grow with preferred orientation in (111) for ZB and (002) for W, perpendiculars to the substrate. Lattice interplanar spacing indicates that the lattice experiences uniaxial contraction along the (111) direction in films grown at Tb in a region near to Tbc . Raman measurements reveal softening of LO in other directions. This compression on the lattice is probably caused by the formation of Cd-vacancies and Cd-interstitials originated by the zincblende-wurtzite phase transformation around Tbc . Highlights: Uniaxial internal stress in CdS nanoparticles by zinc blende-wurtzite transition. 1LO phonon softening of CdS in plane-substrate by cubic-hexagonal transition. CdS lattice compressed along of (111) zinc blende and (002) wurtzite phases. Very sharp zinc blende-wurtzite phase transition of CdS nanoparticles at T∼94 °C.