| || Low-pressure Chemical Vapour Deposition of Silicon Nanoparticles: Synthesis and Characterisation
Author : Kumar, A.;Agarwal, Pankaj B.;Kumar, Sachin;Joshi, B.C.;Sharma, A.K.;Chander, H.
Source : Defence Science Journal ; Vol:58(4) ; 2008 ; pp 550-558
Subject : 620.1 Material Science and Technology;66 Chemical Technology
Keywords : Silicon nanoparticles;Coulomb blockade;Quantum confinement;Tip artifacts;Convolution;Deconvolution;Surface reconstruction;Single electron transistor;Single electron memories
Abstract : Semiconductor nanostructures such as quantum wells, quantum wires or quantum dots exhibit superior properties in comparison to their bulk forms. Quantum dots are described as zero-dimensional electron gas system, as carriers are confined in all the three directions. Density of states is discrete function of energy. Allowed energy spectrum is discrete like in an atom. Energy band gap is broadened due to carriers confinement. Semiconductor quantum dots exhibit typical coulomb blockade characteristic which is exploited for development of new generation of nanoelectronic devices namely single-electron transistor, memories, etc, whose operation depends on quantum mechanical tunneling of carriers through energy barriers. These semiconductor nanostructures emit light in visible range upon excitation by optical means. In recent years, research has been focused on different nano-scale materials; metals (Au, Ag, Fe, Mn, Ni), metal oxides (SnO2, ZnO2), compound semiconductors (GaAs, GaAlAs, CdSe, CdS, GaN), and elemental semiconductors (silicon and germanium). As silicon is the most favoured material in the established integrated circuits manufacturing technology, research is being done for controlled synthesis and characterisation of Si nanoparticles. The Si nanoparticles have been synthesised on oxide and nitride layers over Si substrate by IC technology compatible low-pressure chemical vapour deposition technique. Atomic force microscopy (AFM) characterisation has been extensively carried out on the samples. It is shown that the tip radius and shape of tip lead to less accurate estimate of the actual size. The AFM images have been evaluated based on the real surface topography and shape of the tip. Photoluminescence (PL) studies have been performed to characterise the samples. The PL measurements showed visible light emission from synthesised silicon nanoparticles.