相关论文: Can impact excitation explain efficient carrier mu…

We investigate theoretically the efficiency of intra-molecular hot carrier induced impact ionization and excitation processes in carbon nanotubes. The electron confinement and reduced screening lead to drastically enhanced excitation…

Photo-excitation in solids can trigger a cascade in which multiple particle-hole excitations are generated. We analyze the carrier multiplication cascade of impact excitation processes in graphene and show that the number of pair…

The multiplication rates of hot carriers in CdSe quantum dots are quantified using an atomistic pseudopotential approach and first order perturbation theory. Both excited holes and electrons are considered, and electron-hole Coulomb…

Carrier multiplication (CM), where the absorption of a single photon results in the generation of several electron-hole pairs via impact ionization, plays a pivotal role in the quest for enhancing the performance of solar cells beyond the…

The conversion of light into free electron-hole pairs constitutes the key process in the fields of photodetection and photovoltaics. The efficiency of this process depends on the competition of different relaxation pathways and can be…

Strong electron-electron interactions in graphene are expected to result in multiple-excitation generation by the absorption of a single photon. We show that the impact of carrier multiplication on photocurrent response is enhanced by very…

Carrier multiplication is a non-radiative recombination mechanism that leads to the generation of two or more electron-hole pairs after absorption of a single photon. By reducing the occurrence of dissipative effects, this process can be…

Free electrons or holes can mediate the nonradiative recombination of excitons in carbon nanotubes. Kinematic constraints arising from the quasi one-dimensional nature of excitons and charge carriers lead to a thermal activation barrier for…

Carrier Multiplication (CM) is a Coulomb-driven non-radiative recombination mechanism which leads to the generation of multiple electron-hole pairs after absorption of a single high-energy photon. Recently a new CM process, termed space…

Being a source of clean and renewable energy, the possibility to convert solar radiation in electric current with high efficiency is one of the most important topics of modern scientific research. Currently the exploitation of interaction…

We report the first observation of trions (charged excitons), three-particle bound states consisting of one electron and two holes, in hole-doped carbon nanotubes at room temperature. When p-type dopants are added to carbon nanotube…

One- and two-photon luminescence excitation spectroscopy showed a series of distinct excitonic states in single-walled carbon nanotubes. The energy splitting between one- and two-photon-active exciton states of different wavefunction…

Combining time-dependent density functional calculations for electrons with molecular dynamics simulations for ions, we investigate the dynamics of excited carriers in a (3,3) carbon nanotube at different temperatures. Following an hv=6.8…

The interactions of charged particles with carbon nanotubes may excite electromagnetic modes in the electron gas produced in the cylindrical graphene shell constituting the nanotube wall. This wake effect has recently been proposed as a…

Although van der Waals layered transition metal dichalcogenides from transient absorption spectroscopy have successfully demonstrated an ideal carrier multiplication (CM) performance with an onset of nearly 2Eg,interpretation of the CM…

We demonstrate for the first time that impact ionization (II) [the inverse of Auger recombination (AR)] occurs with very high efficiency in semiconductor nanocrystals (NCs). Interband optical excitation of PbSe NCs at low pump intensities,…

Hot carrier effect, a phenomenon where charge carriers generated by photon absorption remain energetic by not losing much energy, has been one of the leading strategies in increasing solar cell efficiency. Nanostructuring offers an…

We report first-principles calculations of the effects of quasiparticle self-energy and electron-hole interaction on the optical properties of single-walled BN nanotubes. Excitonic effects are shown to be even more important in BN nanotubes…

When the excitation of carriers in real space is focused down to the nanometer scale, the carrier system can no longer be viewed as homogeneous and ultrafast transport of the excited carrier wave packets occurs. In state-of-the-art…

Electronic many-body correlation effects in one-dimensional (1D) systems such as carbon nanotubes have been predicted to modify strongly the nature of photoexcited states. Here we directly probe this effect using broadband elastic light…