Interplay of bimolecular and Auger recombination in photoexcited carrier dynamics in silicon nanocrystal/silicon dioxide superlattices

Abstract

We report results of investigating carrier recombination in silicon nanocrystal/silicon dioxide superlattices. The superlattices prepared by nitrogen-free plasma enhanced chemical vapour deposition contained layers of silicon nanocrystals. Femtosecond transient transmission optical spectroscopy was used to monitor carrier mechanisms in the samples. The three-particle Auger recombination was observed in accord with previous reports. However, under high pump intensities (high photoexcited carrier densities) the bimolecular process dominated the recombination. Detailed analysis of measured data and fitting procedure made it possible to follow and quantify the interplay between the two recombination processes. The bimolecular recombination was interpreted in terms of the trap-assisted Auger recombination.

Ultrafast Carrier Dynamics of Undoped and Ho3+-Doped α-Bismuth Oxide Microrods

“…Since bismuth oxide is an indirect band semiconductor, the possibilities of these recombinations in our system can be neglected. Thus, we attribute τ 2 to trap-assisted Auger recombination, a two-body process (Figure e, black solid line), which has been reported for both direct and indirect band gap materials, − to be the underlying mechanism behind the observed decay process. Here, an electron in conduction band recombines with a deeply trapped hole nonradiatively, transferring the energy to another conduction band electron.…”

Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

“…The pump flux is chosen to generate only a few excitons per NC [ 45 ]. Specifically, 2.3 mJ/cm 2 (SRON) and 3.4 mJ/cm 2 (SRO) were used, which correspond to the excitation regime with normal Auger recombination of excitons, excluding bimolecular recombination [ 46 ]. If an additional free carrier (electron from P-donor or hole from B-acceptor) would be present in a Si NC, the generated exciton(s) could efficiently and quickly recombine with the unpaired charge carrier via an Auger process.…”

Auger Recombination Kinetics of the Free Carriers in Hexagonal Boron Nitride

“…This has a much stronger dependence on the carrier concentration and is often an undesirable process in systems involving high-carrier-density applications such as lasers. The rate constants for this mechanism are often in the range of 10 –26 – 10 –31 cm 6 s –1 (see refs ,− and references therein). The recombination rates for the mechanisms mentioned above have been measured through various experimental techniques, including transient absorption spectroscopy.…”