Ge nanocrystals in SiO2 films

Abstract

SiO 2 /Ge nanocrystal/SiO2 structures have been fabricated by deposition of Ge film on a SiO2 layer and subsequent oxidation of the structure at a temperature between 800 °C and 1000 °C. Secondary ion mass spectrometry results indicate that the Ge precipitates into the bulk SiO2 at a density of 1×1012 cm−2. Raman spectra show a sharp peak at 300 cm−1 for the nanocrystallized Ge. The nanocrystal diameter is determined to be 5 nm on average. In the metal–insulator–silicon structure, electron storage occurs in the SiO2/Ge/SiO2 potential well via electron tunneling into the oxide film. Capacitance-voltage measurements indicate that flatband voltage (VFB) shifts to 0.91 V after the electron injection. The VFB shift is attributed to the charge storing for a single electron per potential well.

Spectroscopic ellipsometric study of Ge nanocrystals embedded in SiO2 using parametric models

“…These suggest Ge departure from the multilayer that needs to be explained. As a matter of fact, thermal diffusion of Ge atoms in SiO 2 towards the substrate was found to be notable in the literature in the case of annealing at high temperatures [17,18].…”

A new solution route to hydrogen-terminated silicon nanoparticles: synthesis, functionalization and water stability

“…This particular size-dependent optical characteristic has been proposed to lead to important applications for the nanoparticles in the applications of optoelectronic devices [3][4][5], light-emitting devices [6], and photopumped tunable lasers. [7] Recently, luminescent silicon nanoparticles have been prepared by a variety of physical and chemical approaches such as electrochemical etching [8], ion implantation [9], thermal vaporization [10], laser ablation [11], and gas phase decomposition of silanes [12,13]. Solution chemistry routes are attractive because particle size and surface chemistry can be controlled simultaneously.…”

Structure and photoluminescence of Ge nanoparticles with different sizes embedded in SiO2 glasses fabricated by a sol–gel method

“…For Ge, most visible photoluminescence (PL) was reported from low-dimensional structures involving Ge nanocrystals embedded in SiO 2 [4][5][6][7][8][9][10][11][12]. Maeda and co-workers [5] observed PL at room temperature in Ge microcrystals embedded in SiO 2 matrix prepared by radio frequency magnetron co-sputtering for the first time.…”