Optical Carrier Multiplication Measurements on Phosphorus and Boron Codoped Silicon
Nanocrystals – Master scriptie Auke Akkerman
Abstract
Carrier multiplication, the generation of multiple carriers upon absorption of a single photon is a
widely studied phenomenon for its prospects in photovoltaics (PV). Silicon nanocrystals show
effective carrier multiplication properties, where the material offers the additional advantage of a
highly developed state of technology. Codoping of silicon nanocrystals with boron and phosphorus
can decrease the photon emission energies of these structures. In this work we show the results of
photoluminescence spectroscopy experiments on boron and phosphorus codoped silicon
nanocrystals. We find an increase of photoluminescence quantum efficiency indicational for a CM
mechanism in codoped NCs with a fundamental energy gap of 1.0 eV, as determined from emission
photon energy. Smaller than that of bulk Si, and close to the theoretical value most efficient for a PV
system with carrier multiplication.
Keywords: nanocrystals, silicon, photoluminescence, carrier multiplication, codoping, quantum
efficiency, boron, phosphor.