High-Quality ZnCdS Nanosheets Prepared Using Solvothermal Synthesis

For the first time, nanosheets with different Zn and Cd ion concentrations were prepared using solvothermal synthesis at 200°C for 4 and 24？h. The crystalline structure of the nanosheets was wurtzite. The optical band gaps of the nanosheets increased with increasing Zn ratio; this increase is consistent with the band gaps estimated using Vegard’s formula. The photoluminescence spectra for the 24？h nanosheets had higher emission intensities than those for the 4？h nanosheets. The emission band corresponding to intrinsic near-band-edge emission and a broad peak associated with extrinsic deep-level emission were observed in the photoluminescence spectra. 1. Introduction One-dimensional (1D) semiconductor nanostructures have recently become widely used because of their special properties: quantum confinement, high surface-to-volume ratio, high optical gain, fast response, and specific crystalline orientation [1–3]. Ternary II–VI semiconductor materials have attracted more interest than binary compounds because some of their properties, such as their tunable optical properties, are better than those of binary compounds. The tunable optical properties of ternary II–VI semiconductor materials can be controlled by appropriately adjusting the constituent mole fractions, particle sizes, and morphologies of the materials [4]. Thus, the formation of led to the control of the optical band gap in a range of ternary phases for CdS (2.42？eV) and ZnS (3.77？eV) [5, 6]. nanocrystalline structures can be obtained using various chemical and physical methods [5, 7–11]. Among the chemical methods, solvothermal synthesis has received considerable attention because of the possibility of preparing high-crystallinity 1D nanostructured materials. Preparation of nanosized metal grids by using lithography led to the fabrication of many types of devices based on single wires, ribbons, belts, and sheets [12–15]. Single 1D nanostructured devices are more efficient and perform better than optoelectronic and gas sensor devices based on thin films [15]. The solvothermal method can produce high-purity nanocrystalline materials with a high degree of crystallinity compared with other solution-based methods [16]. Herein, the nanosheets were synthesized for the first time via the solvothermal method. The effect that reaction time and Zn ratio had on the morphologies, crystalline structures, and optical properties of the nanosheets was investigated. 2. Experimental Section Cadmium chloride (CdCl2), zinc chloride (ZnCl2), and sulfur (S) powders were used as Cd2+, Zn2+, and S2？ ions sources,