Preparation of Ge Nanoparticles by Colloidal Method and their Characterization

In this study, as a blue light source, colloidal germanium nanoparticles were synthesized by a simple method and their optical properties were also studied.Polyvinyl pyrrolidone as a surface modifier and the particle size controller was used. To investigate the optical properties of prepared nanoparticles, UV-Vis absorption, and emission spectroscopy were employed. Fourier Transform InfraRed (FT-IR) spectroscopy was used to determine the type of chemical bond. FT-IR spectrum indicates that the germanium nanocrystals are well passivated with minimal surface oxidation. TEM was used to confirm particle size and morphology.Experimental results showed that the synthesized Ge nanoparticles have a spherical shape with size variation between 5 to 10 nm. Germanium nanoparticles exhibit blue light-emitting with PL peak located at 445 nm. Also, the direct optical band gap of Ge colloidal nanocrystals was evaluated by Tauc's theory. The direct band gap energy value of Ge colloidal nanocrystals is equal to 3.12 eV. The crystallinity of Ge nanoparticles was also evaluated by X-ray diffraction pattern analysis.