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

Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions

Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties. By adjusting parameters of contact- and tapping-mode atomic force microscopy (AFM), we perform morphologic and mechanical characterizations (nanoshaving) of organic layers, measure their electrical conductivity by current-sensing AFM, and deduce work functions and surface photovoltage (SPV) effects by Kelvin force microscopy using high spatial resolution. These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data. We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond

Strukturální, optické a mechanické vlastnosti tenkých diamantových vrstev a tenkých vrstev karbidu křemíku deponovaných mikrovlnnou plasmou podpořenou chemickou plynnou depozicí s rozvodem lineární anténou za nízkého tlaku

In this work, we detail the properties of thin silicon carbide and polycrystalline diamond layers grown by microwave plasma enhanced chemical vapour deposition with linear antenna delivery. Structural, mechanical and optical properties are compared for their potential use as transparent hard coatings. Silicon carbide layers exhibit mechanical properties comparable to thin diamond layers but with a significantly higher adhesion and lower optical absorption coefficient over a wide spectral range.V tomto článku jsou studovány vlastnosti karbidu křemíku a polykrystalických diamantových vrstev deponovaných mikrovlnnou plasmou podpořenou chemickou plynnou depozicí s rozvodem lineární anténou za nízkého tlaku. Jejich strukturální, mechanické a optické vlastnosti jsou porovnány s ohledem na jejich potenciální využití v oblasti transparentních tvrdých potahů. Karbid křemíku vykazuje mechanické vlastnosti porovnatelné s tenkými diamantovými vrstvami, ale podstatně vyšší adhezi a nižší absorpční koeficient v širokém spektrálním oboru