Photoluminescence study of Si1-xGex nanoparticles in various oxide matrices

We investigate the photoluminescence properties of structures comprising of Si
1-x
Ge
x
nanoparticles (NPs) within SiO
2
, GeO
2
, TiO
2
and Ta
2
O
5
oxide matrices. Of the investigated structures, it was observed that the structures with GeO
2
and TiO
2
matrices provide increased spectral response (at ~907 and 844 nm respectively) and increased PL intensity. The improved PL characteristic have been attributed to increased diffusion barrier against oxygen which otherwise would result in formation of unwanted oxide at the film-oxide interface, thereby deteriorating the optical properties.