Origin of photoluminescence peaks in Ge–SiO₂ thin films

Abstract

Ge-SiO 2 thin films were prepared by the RF magnetron sputtering technique on p-Si substrates from a Ge -SiO 2 composite target. The asdeposited films were annealed in the temperature range of 300 -1000 8C under nitrogen ambience. The structure of films was evaluated by X-ray diffraction, X-ray photoemission spectroscopy and Fourier transform infrared absorption spectroscopy. Results show that the content of Ge and its oxides in the films change with increasing annealing temperature ðT a Þ; the photoluminescence (PL) characteristics are closely dependent on the contents of Ge and its oxides in SiO 2 matrix. The dependence observed strongly suggests that the PL peak at 394 nm is related to the existence of GeO and 580 nm to that of Ge nanocrystal (nc-Ge) in the films.

Formation of ST12 phase Ge nanoparticles in ZnO thin films

“…As much as the freestanding Ge nanoparticles would be useful for applications based on physicochemical properties, an embedding medium is usually required for photovoltaic or optoelectronic applications where a path for the transport of light generated charge carriers is needed. Current literature mostly utilizes SiO 2 as the embedding medium due to already developed Si based processing technology [16][17][18][19]. However, ZnO is also suggested to be a potential candidate especially for photovoltaic applications [20,21].…”