Preparation of Ge Nanoparticles by Colloidal Method and their Characterization

Document Type : Research Article


1 Science Faculty, Tehran Markaz Branch, Islamic Azad University, Tehran, I.R. IRAN

2 Laser & Optics Research School, NSTRI, 11155-3486, Tehran, I.R. IRAN


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.


Main Subjects

[1] Ghosh B., Sakka Y., Shirahata N., Efficient Green-Luminescent Germanium Nanocrystals, Journal of Materials Chemistry, A1: 3747-7751 (2013).
[2] Shirahata N., Hirakawa D., Masuda Y., Sakka Y., Size-Dependent Color Tuning of Efficiently Luminescent Germanium Nanoparticles, Langmuir, 29: 7401-7410 (2012).
[3] Ray S., Maikap S., Banerjee W., Das S., Nanocrystals for Silicon-Based Light-Emitting and Memory Devices, J. Phys. D: Appl. Phys., 46: 153001-153031 (2013).
[4] Vaughn Ii D.D., Schaak R.E., Synthesis, Properties and Applications of Colloidal Germanium and Germanium-Based Nanomaterials, Chem. Soc. Rev., 42: 2861-2879 (2013).
[5] Holman Z.C., Kortshagen U.R., Absolute Absorption Cross Sections of Ligand-Free Colloidal Germanium Nanocrystals, Appl. Phys. Lett., 100: 133108 (2012).
[6] Wu J., Sun Y., Zou R., Song G., Chen Z., Wang C., Hu J., One-Step Aqueous Solution Synthesis of Ge Nanocrystals from GeO2 Powders, Cryst. Eng. Comm., 13: 3674-3677 (2011).
[7] Taylor B.R., Fox G.A., Hope-Weeks L.J., Maxwell R.S., Kauzlarich S.M., Lee H.W.H., Solution Preparation of Ge Nanoparticles with Chemically Tailored Surfaces, Mater. Sci. and Eng. B, 96: 90-93 (2002)
[8] Seo M.A., Kim D.S., Kim H.S., Choi D.S., Jeoung S.C., Formation of Photoluminescent Germanium Nanostructures by Femtosecond Laser Processing on Bulk Germanium: Role of Ambient Gases, Opt. Express, 14 (11): 4908-4914 (2006).
[9] Thomas F. Fassle, “Zintl Phases: Principles and Recent Developments”, Springer-Verlag Berlin Heidelberg (2011).
[10] Chou N.H., Oyler K.D., Motl N.E., Schaak R.E., Colloidal Synthesis of Germanium Nanocrystals Using Room-Temperature Bench Top Chemistry, Chem. Mater. 21(18): 4105-4107 (2009).
[11] Hellstrom P., Holmgren A., Oberg S., An Ab Initio Study of Ethyl Xanthate Adsorbed on Ge(111) Surfaces, J. Phys. Chem. C, 111: 16920–16926 (2007).
[12] Chang J., Waclawik E.R., Colloidal Semiconductor Nanocrystals: Controlled Synthesis and Surface Chemistry in Organic Media, RSC Adv., 4: 23505–23527 (2014).
[13] Rimer J.D., Roth D.D., Vlachos D.G., Lobo R.F., Self-Assembly and Phase Behavior of Germanium Oxide Nanoparticles in Basic Aqueous Solutions, Langmuir, 23: 2784-2791 (2007).
[15] Jing C., Zang X., Bai W., Chu J., Liu A., Aqueous Germanate Ion Solution Promoted Synthesis of Worm-Like Crystallized Ge Nanostructures under Ambient Conditions, Nanotechnology, 20: 505607 (2009).
[16] Hund Z.M., Nihill K.J., Campi D., Wong K.T., Lewis N.S., Bernasconi M., Benedek G., Sibener S.J., Atomic Surface Structure of CH3-Ge(111) Characterized by Helium Atom Diffraction and Density Functional Theory, J. Phys. Chem. C, 119: 18458−18466 (2015).
[17] Gazicki M., Szymanowski H., Tyczkowski J., Malinovsky L., Schalko J., Fallmann W., Chemical Bonding in Thin Ge/C Films Deposited from Tetraethylgermanium in an r.f. Glow Discharge-An FT-IR Study, Thin Solid Films, 256: 31-38 (1995).
[18] Henderson E.J., Seino M., Puzzo D.P., Ozin G.A., Colloidally Stable Germanium Nanocrystals for Photonic Applications, ACS Nano, 4(12): 7683-7691 (2010).
[19] Lee D.C., Pietryga J.M., Robel I., Werder D.J., Schaller R.D., Klimov V.I., Colloidal Synthesis of Infrared-Emitting Germanium Nanocrystals, J. Am. Chem. Soc., 131(10): 3436-3437 (2009).
[20] Carolan D., Doyle H., Size and Emission Color Size and Emission Color Tuning in the Solution Phase Synthesis of Highly Luminescent Germanium Nanocrystals, J. Mater. Chem. C, 2: 3562-3568 (2014).
[21] Wilcoxon J.P., Provencio P.P., Samara G.A., Synthesis and Optical Properties of Colloidal Germanium Nanocrystals, Phys. Rev. B, 64: 035417 (2001).