2019/05/29 by Katerina Dohnalova Newell, Prokop Hapala, Newell, Katerina Dohnalova +5
Engineering · Materials Science · #Boron and Carbon Nanomaterials Research #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Semiconductor materials and devices #Silicon Nanostructures and Photoluminescence
paper · pdf · doi:10.48550/arxiv.1905.12371
openalex publication_date 2019/05/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It is widely accepted that the properties of most semiconductor nanocrystals\ncan be tuned by their core size, shape and material. In covalent semiconductor\nnanocrystal materials, such as silicon, germanium or carbon, certain degree of\ntunability of the properties can be also achieved by the surface ligands. In\nparticular, covalently bonded ligand species on the surface of such a\nnanocrystal (i) contribute to the density of states of the core via orbital\ndelocalization; (ii) might introduce strain via ligand-to-ligand steric\nhindrance and (iii) will cause charge transfer from/to the core. In this work\nwe study all these effects on silicon nanocrystals (SiNCs). We analyze\ngeometrically optimized ~ 2 nm SiNCs with electronegative organic ligands using\ndensity functional theory (DFT) simulations. We show that the radiative rate is\nenhanced by electronegative alkyl and fluorocarbon with respect to what is\nexpected from quantum confinement effect, while bandgap remains unchanged.\nAlso, we show that tensile strain caused by the ligand steric hindrance is\ndetrimental to the rate enhancement, contrary to the positive effects of the\nmore homogeneous tensile strain induced in pressure cell.\n