Časově rozlišené měření optického zisku křemíkových nanostruktur

Ondič, Lukáš

2 Title: Time-resolved measurement of optical gain in silicon based nanostructures Author: Bc. Lukáš Ondič Department: Department of Chemical Physics and Optics Supervisor: Prof. RNDr. Ivan Pelant, DrSc., Institute of Physics, Academy of Sci- ences of the Czech Republic Supervisor's email address: pelant@fzu.cz Abstract: The aim of this work is to study the optical properties of the mate- rial based on oxidized silicon nanocrystals (Si-ncs) embedded at high densities in SiO2-based matrix. These materials seem to be very promising on the way towards silicon laser. Using our preparation technique - modified electrochemical etching and post-etching in H2O2 - we obtain small Si-ncs with the mean core size of 2-3 nm, in- corporated at high densities of ∼ 1019 Si-ncs/cm3 into an SiO2-based matrix. In this work, we focused on studying their photoluminiscence (PL) properties and measuring the net optical gain of these samples. Therefore, we investigated their time-resolved and steady-state PL emission spectra which revealed two emission bands - the F-band (∼ 435 nm) with ns decay-time and the S-band (∼ 600 − 620 nm) with µs decay- time. Moreover, we observed a "green" emission band (∼ 500 nm) present only during the pulsed excitation and immediately after. We performed time-resolved gain spec- troscopy using...

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