Carrier-Multiplication-Induced Structural Change during Ultrafast Carrier Relaxation and Nonthermal Phase Transition in Semiconductors

Ultrafast collinear scattering and carrier multiplication in graphene.

Graphene is emerging as a viable alternative to conventional optoelectronic, plasmonic and nanophotonic materials. The interaction of light with charge carriers creates an out-of-equilibrium distribution, which relaxes on an ultrafast timescale to a hot Fermi-Dirac distribution, that subsequently cools emitting phonons. Although the slower relaxation mechanisms have been extensively investigate...

Ultrafast Processes in Semiconductors: Coherent Polarizations Carrier Dynamics

Understanding the relationship between structure and function represents a central issue of basic materials research. Fundamental physical, chemical and/or biological properties and functions of materials are determined by the dynamics of elementary excitations in the ultrafast time domain, i.e. between 1 fs (1 femtosecond = 10 s) and approximately 1 ps ( 1 picosecond = 10 s). Such nonequilibri...

Carrier-envelope-offset phase control of ultrafast optical rectification in resonantly excited semiconductors.

Ultrashort pulse light-matter interactions in a semiconductor are investigated within the regime of resonant optical rectification. Using pulse envelope areas of around 1.5-3.5 pi, a single-shot dependence on carrier-envelope-offset phase (CEP) is demonstrated for 5 fs pulse durations. A characteristic phase map is predicted for several different frequency regimes using parameters for thin-film...

Ultrafast hole carrier relaxation dynamics in p-type CuO nanowires

Ultrafast hole carrier relaxation dynamics in CuO nanowires have been investigated using transient absorption spectroscopy. Following femtosecond pulse excitation in a non-collinear pump-probe configuration, a combination of non-degenerate transmission and reflection measurements reveal initial ultrafast state filling dynamics independent of the probing photon energy. This behavior is attribute...

Excess Carrier Phenomenon in Semiconductors