title: Modification of the nonlinear optical absorption and optical Kerr response exhibited by nc-Si embedded in a silicon-nitride film.
abstract: We studied the absorptive and refractive nonlinearities at 532 nm and 26 ps pulses for silicon-nitride films containing silicon nanoclusters (nc-Si) prepared by remote plasma-enhanced chemical vapor deposition (RPECVD). Using a self-diffraction technique, we measured for the as-grown sample beta=7.7x10(-9)m/W, n(2)=1.8x10(-16)m(2)/W, and /chi(3)1111/ = 4.6x10(-10)esu; meanwhile, when the sample was exposed to an annealing process at 1000 degrees C during one hour in a nitrogen atmosphere, we obtained beta=-5x10(-10)m/W, n2=9x10(-17)m(2)/W, and /chi(3)1111/=1.1x10(-10)esu. A pure electronic nonlinear refraction was identified and a large threshold ablation of 41 J/cm(-2) was found for our films. By fitting nonlinear optical transmittance measurements, we were able to estimate that the annealed sample exhibits a response time close to 1 fs. We report an enhancement in the photoluminescence (PL) signal after the annealing process, as well as a red-shift due to an increment in size of the nc-Si during the thermal process.
authors.affiliation: Instituto de Física, Universidad Nacional Autónoma de México, México, DF, México.
authors.forename: A
authors.initials: A
authors.lastname: López-Suárez
authors.forename: C
authors.initials: C
authors.lastname: Torres-Torres
authors.forename: R
authors.initials: R
authors.lastname: Rangel-Rojo
authors.forename: J A
authors.initials: JA
authors.lastname: Reyes-Esqueda
authors.forename: G
authors.initials: G
authors.lastname: Santana
authors.forename: J C
authors.initials: JC
authors.lastname: Alonso
authors.forename: A
authors.initials: A
authors.lastname: Ortiz
authors.forename: A
authors.initials: A
authors.lastname: Oliver
mesh_terms: D000042:Absorption; D003198:Computer Simulation; D008027:Light; D008567:Membranes, Artificial; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D017711:Nonlinear Dynamics; D012542:Scattering, Radiation; D017655:Silicon Compounds / Q000737:chemistry*
chemical_list: D008567:Membranes, Artificial; D017655:Silicon Compounds; C032734:silicon nitride