Growth of CdS nanosheets and nanowires through the solvothermal method

Cadmium sulfide (CdS) nanocrystalline structures were grown through the solvothermal method at various temperatures (100, 120, 160, and 200 °C) for 7 h using ethylenediamine as the solvent. Two different CdS nanostructures were prepared: nanosheets were prepared at 100 and 120 °C and nanowires at 160 and 200 °C. The nanowire diameter ranged a few tens of nanometers, and the length reached several micrometers. The grown nanosheets and nanowires had a hexagonal wurtzite crystalline structure, as estimated from the X-ray diffraction pattern analysis. The growth direction of the nanowires grown at 160 and 200 °C was along <001>. The optical band gaps of the CdS nanosheets prepared at 100 and 120 °C were 3.25 and 2.42 eV, respectively, and 2.55 and 2.59 eV for the nanowires prepared at 160 and 200 °C, respectively. The photoluminescence spectra of the prepared nanostructures were analyzed. Results revealed that emission peak location and intensity depend on structure type and morphology. A single sharp emission peak at 480 nm was observed for the CdS nanowire grown at 200 °C, which was close to the absorption band edge.

► CdS nanosheets and nanowires were prepared through the solvothermal method.
► The crystalline structure of the grown nanosheets and nanowires was hexagonal.
► Nanowire growth direction was along <001>.
► The optical band gaps of the nanosheets and nanowires were blue-shifted.
► At high temperature, the nanowires showed strong single PL emission.