Time-resolved nonlinear optical-holographic techniques for investigation of non-equilibrium carrier dynamics in semiconductors

2011 ◽  
Author(s):  
Kestutis Jarašiūnas
Keyword(s):  
Nonlinear Optical ◽  
Carrier Dynamics ◽  
Time Resolved ◽  
Non Equilibrium

Optical Characterization of Compensating Defects in Cubic SiC

2013 ◽  
Vol 740-742 ◽  
pp. 401-404
Author(s):  
Patrik Ščajev ◽  
K. Jarašiūnas ◽  
P.L. Abramov ◽  
S.P. Lebedev ◽  
A.A. Lebedev
Keyword(s):  
Carrier Density ◽  
Nonlinear Optical ◽  
Carrier Lifetime ◽  
Optical Trap ◽  
Optical Characterization ◽  
Carrier Dynamics ◽  
Time Resolved ◽  
Carrier Recombination ◽  
P Type

We present investigation of carrier recombination and optical trap recharge in sublimation grown n- and p-type 3C layers by using time-resolved nonlinear optical techniques. Carrier lifetime and recharged trap recovery were measured by differential transmittivity technique. By monitoring nonequilibrium carrier dynamics, we analyzed impact of carrier density and temperature on carrier lifetime and recharged trap recovery rate. Large carrier lifetime and small diffusivity at low injections in highly compensated samples and their dependences on injection were explained by optical recharge of compensating aluminum impurities. The complete recharge of the compensating impurities by optical means allowed us to calculate the compensating aluminum density in n-type samples and compensating nitrogen in p-type ones.

Advantages of the time-resolved four-wave mixing technique for studies of non-equilibrium carrier dynamics in bulk semiconductors and structures

2008 ◽  
Vol 30 (5) ◽  
pp. 780-782 ◽  
Author(s):  
R. Aleksiejunas ◽  
A. Kadys ◽  
T. Malinauskas ◽  
K. Neimontas ◽  
V. Gudelis ◽  
...  
Keyword(s):  
Four Wave Mixing ◽  
Carrier Dynamics ◽  
Wave Mixing ◽  
Time Resolved ◽  
Bulk Semiconductors ◽  
Non Equilibrium

scholarly journals Effects of Crystal Morphology on the Hot-Carrier Dynamics in Mixed-Cation Hybrid Lead Halide Perovskites

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 708
Author(s):  
Daniele Catone ◽  
Giuseppe Ammirati ◽  
Patrick O’Keeffe ◽  
Faustino Martelli ◽  
Lorenzo Di Mario ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Carrier Dynamics ◽  
Large Area ◽  
Photovoltaic Properties ◽  
Time Resolved ◽  
Hot Carrier ◽  
Mixed Cation ◽  
Small Crystals ◽  
Characterization Of Materials ◽  
Lead Halide

Ultrafast pump-probe spectroscopies have proved to be an important tool for the investigation of charge carriers dynamics in perovskite materials providing crucial information on the dynamics of the excited carriers, and fundamental in the development of new devices with tailored photovoltaic properties. Fast transient absorbance spectroscopy on mixed-cation hybrid lead halide perovskite samples was used to investigate how the dimensions and the morphology of the perovskite crystals embedded in the capping (large crystals) and mesoporous (small crystals) layers affect the hot-carrier dynamics in the first hundreds of femtoseconds as a function of the excitation energy. The comparative study between samples with perovskite deposited on substrates with and without the mesoporous layer has shown how the small crystals preserve the temperature of the carriers for a longer period after the excitation than the large crystals. This study showed how the high sensitivity of the time-resolved spectroscopies in discriminating the transient response due to the different morphology of the crystals embedded in the layers of the same sample can be applied in the general characterization of materials to be used in solar cell devices and large area modules, providing further and valuable information for the optimization and enhancement of stability and efficiency in the power conversion of new perovskite-based devices.

scholarly journals A time-domain phase diagram of metastable states in a charge ordered quantum material

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jan Ravnik ◽  
Michele Diego ◽  
Yaroslav Gerasimenko ◽  
Yevhenii Vaskivskyi ◽  
Igor Vaskivskyi ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Time Domain ◽  
Metastable States ◽  
Scanning Tunneling ◽  
Photon Density ◽  
Tunneling Microscopy ◽  
Equilibrium Conditions ◽  
Time Resolved ◽  
A Charge ◽  
Non Equilibrium

AbstractMetastable self-organized electronic states in quantum materials are of fundamental importance, displaying emergent dynamical properties that may be used in new generations of sensors and memory devices. Such states are typically formed through phase transitions under non-equilibrium conditions and the final state is reached through processes that span a large range of timescales. Conventionally, phase diagrams of materials are thought of as static, without temporal evolution. However, many functional properties of materials arise as a result of complex temporal changes in the material occurring on different timescales. Hitherto, such properties were not considered within the context of a temporally-evolving phase diagram, even though, under non-equilibrium conditions, different phases typically evolve on different timescales. Here, by using time-resolved optical techniques and femtosecond-pulse-excited scanning tunneling microscopy (STM), we track the evolution of the metastable states in a material that has been of wide recent interest, the quasi-two-dimensional dichalcogenide 1T-TaS2. We map out its temporal phase diagram using the photon density and temperature as control parameters on timescales ranging from 10−12 to 103 s. The introduction of a time-domain axis in the phase diagram enables us to follow the evolution of metastable emergent states created by different phase transition mechanisms on different timescales, thus enabling comparison with theoretical predictions of the phase diagram, and opening the way to understanding of the complex ordering processes in metastable materials.

Optical, electrochemical and third-order nonlinear optical studies of triphenylamine substituted zinc phthalocyanine

2016 ◽  
Vol 20 (08n11) ◽  
pp. 1173-1181 ◽  
Author(s):  
Narra Vamsi Krishna ◽  
Puliparambil Thilakan Anusha ◽  
S. Venugopal Rao ◽  
L. Giribabu
Keyword(s):  
Nonlinear Optical ◽  
Emission Spectra ◽  
Optical Emission ◽  
Soret Band ◽  
Laser Pulses ◽  
Zinc Phthalocyanine ◽  
Third Order ◽  
Time Resolved ◽  
Nlo Properties ◽  
Scan Data

Zinc phthalocyanine possessing triphenylamine at its peripheral position has been synthesized and its optical, emission, electrochemical and third-order nonlinear optical (NLO) properties were investigated. Soret band was broadened due to the presence of triphenylamine moiety. Electrochemical properties indicated that both oxidation and reduction processes were ring centered. Emission spectra were recorded in different solvents and the fluorescence yields obtained were in the range of 0.02–0.17 while the time-resolved fluorescence data revealed radiative lifetimes of typically few ns. Third-order NLO properties of this molecule have been examined using the Z-scan technique with picosecond (ps) and femtoseocnd (fs) pulses. Closed and open aperture Z-scan data were recorded with 2 ps/1 50 fs laser pulses at a wavelength of 800 nm and NLO coefficients were extracted from both the data. Our data clearly suggests the potential of this molecule for photonics applications.

Few-Particle Effects in Nonlinear Optical Spectra of Semiconductor Quantum Dots

1999 ◽  
Vol 571 ◽  
Author(s):  
Ulrich Hohenesteri ◽  
Fausto Rossi ◽  
Elisa Molinari
Keyword(s):  
Quantum Dots ◽  
Density Matrix ◽  
Nonlinear Optical ◽  
Coherent Control ◽  
Optical Spectra ◽  
Carrier Dynamics ◽  
Semiconductor Quantum Dots ◽  
Nonequilibrium Carrier ◽  
Optical Nonlinearities ◽  
Matrix Approach

ABSTRACTWe present a density-matrix approach for the description of nonequilibrium carrier dynamics in optically excited semiconductor quantum dots, that explicitly accounts for exciton-exciton as well as exciton-carrier interactions. Within this framework, we analyze few-particle effects in the optical spectra and provide a consistent description of additional peaks appearing at high photoexcitation density. We discuss possible applications of such optical nonlinearities in future coherent-control experiments.

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