We investigate the impact of phonon excitations on photoexcited carrier dynamics in a lead-halide perovskite ${\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}$, which hosts unique low-energy phonons that can be directly excited by terahertz pulses. Our time-resolved photoluminescence measurements reveal strong excitation prolongs cooling time hot carriers, providing direct evidence for hot-...

Abstract Effect of laser wavelength on the carrier-phonon dynamics and damage threshold silicon is studied numerically. Laser excitation in using Three-Temperature Model (3TM). We consider evolution electron, hole, lattice temperatures separately including band-gap re-normalization effect optical properties silicon. Finite Difference Time Domain method used to model field. Damage calculated 3TM...

We determine the spin-lifetime anisotropy of spin-polarized carriers in graphene. In contrast to prior approaches, our method does not require large out-of-plane magnetic fields and thus it is reliable for both low- and high-carrier densities. We first determine the in-plane spin lifetime by conventional spin precession measurements with magnetic fields perpendicular to the graphene plane. Then...

Infrared spectroscopy is used to investigate the electronic structure and charge carrier relaxation in crystalline films of CrO2 which is the simplest of all half-metallic ferromagnets. Chromium dioxide is a bad metal at room temperature but it has a remarkably low residual resistivity (,5 mV cm) despite the small spectral weight associated with free carrier absorption. The infrared measurement...

We present results of out-of-equilibrium transport measurements made on strongly localized Beryllium films and demonstrate that these films exhibit all the earmarks of intrinsic electron glasses. These include slow logarithmic relaxation, memory effects, and more importantly, the observation of a memory dip that has a characteristic width compatible with the carrier concentration of beryllium. ...

A space- and time-dependent theoretical model based on a trap-assisted, charge-transport framework for the amorphous phase of chalcogenide material is used here to interpret available experimental results electric current nanoscale devices in ns–ps time domain. numerical solution constitutive equations bias has been carried out GST-225 devices. The “intrinsic” rise device after application suit...

background: fatigue is one of the important factors in nursing performance because it affects the quality of care provided to the patients. in this regard, some complementary interventions such as benson relaxation techniques may relieve fatigue. this study aimed to evaluate the effect of benson relaxation on fatigue of nurses working in intensive care units. methods: this is an experimental st...

We have studied ultrafast carrier dynamics in nanocrystalline silicon films with thickness of a few nanometers where boundary-related states and quantum confinement play an important role. Transient non-degenerated photoinduced absorption measurements have been employed to investigate the effects of grain boundaries and quantum confinement on the relaxation dynamics of photogenerated carriers. ...

Using ultrafast optical pump-probe spectroscopy, we study the relaxation dynamics of hot optical phonons in few-layer and multilayer graphene films grown by epitaxy on silicon carbide substrates and by chemical vapor deposition on nickel substrates. In the first few hundred femtoseconds after photoexcitation, the hot carriers lose most of their energy to the generation of hot optical phonons wh...

Ionized-impurity scattering is an anisotropic process showing a high preference for small scattering angles. In a Monte Carlo simulation of a semiconductor device many small-angle scattering events have to be processed, although the contribution of these events to carrier momentum relaxation is small. A new method is presented which reduces the amount of smallangle scattering very effectively. ...