Effects of Temperature on the Morphology and Optical Properties of Spark Discharge Germanium Nanoparticles

Authors :: E. S. Khramov
Anastasia Mazharenko
A. A. Lizunova
B. I. Masnaviev
V. V. Ivanov
I. A. Shuklov
A. A. Efimov
A. A. Ramanenka
Source :: Materials, Vol 13, Iss 4431, p 4431 (2020), Materials, Volume 13, Issue 19
Publication Year :: 2020
Publisher :: MDPI AG, 2020.
Abstract: We report the spark discharge synthesis of aerosol germanium nanoparticles followed by sintering in a tube furnace at different temperatures varying from 25 to 800 &deg<br />C. The size, structure, chemical composition and optical properties were studied. We have demonstrated a melting mechanism of nanoparticles agglomerates, the growth of the mean primary particle size from 7 to 51 nm and the reduction of the size of agglomerates with a temperature increase. According to transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) data, primary nanoparticles sintered at temperatures from 25 to 475 &deg<br />C basically have a structure of Ge crystals embedded in a GeOx amorphous matrix, as well as visible photoluminescence (PL) with the maximum at 550 nm. Pure germanium nanoparticles are prepared at temperatures above 625 &deg<br />C and distinguished by their absence of visible PL. The shape of the experimental UV-vis-NIR extinction spectra significantly depends on the size distribution of the germanium crystals. This fact was confirmed by simulations according to Mie theory for obtained ensembles of germanium nanoparticles.

Tools