5:00 PM - EQ08.04.04
Auto-Formation of Silicon Quantum Dots Embedded in a Silicon Nitride Matrix—The Role of the Substrate
Instituto de Física - Universidad Nacional Autónoma de México1
Proper control of the luminescence from silicon quantum dots (SiQDs) would allow their commercial use in technologies ranging from artificial lighting to optical computing applications [1,2]. Imbibe SiQDs in a silicon nitride (Si3N4) thin film is a good option for technology transfer because Si3N4 has a good concentration of charge carriers and a moderate band gap that enables low turn-on voltages in operational devices .
Multiple studies have shown that the quantum confinement effect is largely responsible for the absorption-emission characteristics of SiQDs embedded in a Si3N4 matrix [4–6]. In other words, it is possible to tailor (within certain limits) absorption, emission, or both by changing the SiQDs average size and population density in those systems . This design capability makes these systems very attractive because they can be used in electroluminescent or optoelectronic devices, sensors, and solar cells [8,9].
In this work, we present a comprehensive analysis based primarily on High-Resolution Transmission Electron Microscopy (HRTEM) to report the SiQDs characteristics of five embedded systems. Each system was grown by RPECVD on the surface of a single-crystalline n-type (100) silicon wafer, fused silica, highly oriented pyrolytic graphite (HOPG), muscovite mica, and single-crystalline potassium chloride. We found that the growths on single crystalline silicon and fused silica have SiQDs with better luminescence characteristics, i.e., reduced average size and high population density. These two substrates are followed by the HOPG, which also exhibits acceptable SiQDs properties. Meanwhile, muscovite mica and potassium chloride show the worst SiQDs characteristics, i.e., bigger average sizes and populations without normal distributions. We conclude that chemical affinity between the substrate and the precursor gases is the most critical parameter to achieve SiQDs formation and reproducibility.
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