Solubility of Sn in Ge network gives it a preference
for photonic
applications, because of the direct transition in GeSn alloy. Here,
we employed the metal-induced crystallization (MIC) process of amorphous
Ge and Si via Sn as a novel mechanism to incorporate Sn inside Ge
and Si networks. (Al/Si/Sn/Ge/Sn) and (Al/Ge/Sn/Ge/Sn) multilayers
are deposited by thermal vacuum evaporation on different substrates.
The devices are annealed under low vacuum at 500 °C to incorporate
the oxygen for band-gap tuning. The structure of Ge-doped nanocrystals
is investigated. The direct transition and band-gap values have been
estimated using diffuse reflectance spectroscopy and photoluminescence
(PL) measurements. PL indicated that the junctions have emissions
from visible to NIR regions that make them promising as optically
pumped white-light sources as well as waveguide applications, and
the impact of the base substrate on enhancing the emission has been
investigated via PL measurements. Electroluminescence measurements
show that the prepared heterostructures on fluorine-doped tin oxide
(FTO) substrate have sharp random lasing spikes over the range of
PL samples spectra as the sample can lase randomly by light scattering
through the Ge-doped nanocrystalline materials. The charge carrier
lifetime measurements show high lifetime for the prepared sample.
These give them the chance to be a candidate for white-light random
laser diode applications.