INFRARED PHOTOLUMINESCENCE SPECTRA OF PBS NANOPARTICLES PREPARED BY LANGMUIR–BLODGETT AND LASER ABLATION METHODS

We optimized the optical setup originally designed for the photoluminescence measurements in the spectral range 400‒1100 nm. New design extends the spectral range into the near infrared region 900‒1700 nm and allows the colloidal solutions measurements in cuvettes as well as the measurements of nanoparticles deposited in the form of thin films on glass substrates. The infrared photoluminescence spectra of the PbS nanoparticles prepared by the Langmuir–Blodgett technique show the higher photoluminescence intensity and the shift to the shorter wavelengths compared to the infrared photoluminescence spectra of the PbS nanoparticles prepared by the laser ablation from PbS target. We aslo proved the high stability of PbS nanoparticles prepared in the form of thin layers

In-situ formation of magnesium silicide nanoparticles on the surface of the hydrogenated silicon films

The magnesium silicide nanoparticles were formed on the surface of hydrogenated silicon thin films by thermal evaporation, annealing and hydrogen plasma treatment. The high reactivity of silicon and magnesium leads to the self-formation of magnesium silicide nanoparticles (NPs). The reaction is stimulated in-situ by the low pressure hydrogen plasma. The presence of Mg2Si NPs was confirmed by SEM and Raman spectroscopy. The photothermal deflection spectroscopy (PDS) shows the enhanced optical absorption in the near infrared spectrum. The diode structures with insitu embedded Mg2Si NPs were characterized by the volt-ampere measurements in dark and under AM1.5 spectrum

Electroluminescence of thin film

Hydrogenated amorphous substoichiometric silicon carbon alloys (a-SiC:H) with and without embedded Ge nanoparticles (NPs) have been prepared by plasma enhanced chemical vapour deposition combined with in-situ Ge evaporation and annealing on semi-transparent boron doped nano-crystalline diamond coated Ti grids. The presence of Ge NPs embedded in the amorphous phase has been confirmed by transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses. Current-voltage (I–V) characteristics and near infrared electroluminescence (EL) spectra were measured to compare performance of diodes. The relatively strong EL appears in diodes with integrated Ge NPs near the direct band-gap transition of Ge at about 0.82 eV with an intensity strongly correlating with current density. However, it has also been found that Ge NPs integrated into a-SiC:H significantly deteriorates diode I–V characteristic