title: Opto-structural studies of well-dispersed silicon nano-crystals grown by atom beam sputtering.
abstract: Synthesis and characterization of nano-crystalline silicon grown by atom beam sputtering technique are reported. Rapid thermal annealing of the deposited films is carried out in Ar + 5% H2 atmosphere for 5 min at different temperatures for precipitation of silicon nano-crystals. The samples are characterized for their optical and structural properties using various techniques. Structural studies are carried out by micro-Raman spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy, and selected area electron diffraction. The optical properties are studied by photoluminescence and UV-vis absorption spectroscopy, and bandgaps are evaluated. The bandgaps are found to decrease after rapid thermal treatment. The micro-Raman studies show the formation of nano-crystalline silicon in as-deposited as well as annealed films. The shifting and broadening in Raman peak suggest formation of nano-phase in the samples. Results of micro-Raman, photoluminescence, and TEM studies suggest the presence of a bimodal crystallite size distribution for the films annealed at higher temperatures. The results show that atom beam sputtering is a suitable technique to synthesize nearly mono-dispersed silicon nano-crystals. The size of the nano-crystals may be controlled by varying annealing parameters.
authors.affiliation: Inter University Accelerator Centre, P,O, Box 10502, Aruna Asaf Ali Marg, New Delhi, 110 067, India. n1saxena@gmail.com.
authors.forename: Nupur
authors.initials: N
authors.lastname: Saxena
authors.forename: Pragati
authors.initials: P
authors.lastname: Kumar
authors.forename: Debulal
authors.initials: D
authors.lastname: Kabiraj
authors.forename: Dinakar
authors.initials: D
authors.lastname: Kanjilal