Interaction of excitons with carriers accelerated by the electric field of a surface acoustic wave in type-II GaAs/AlAs superlattices

2012 ◽  
Vol 86 (16) ◽  
Author(s):  
D. V. Gulyaev ◽  
K. S. Zhuravlev
Keyword(s):  
Acoustic Wave ◽  
Electric Field ◽  
Surface Acoustic Wave ◽  
Type Ii

Mechanisms of exciton photoluminescence quenching in the electric field of a standing surface acoustic wave

2019 ◽  
Vol 33 (06) ◽  
pp. 1950032
Author(s):  
D. V. Gulyaev ◽  
K. S. Zhuravlev
Keyword(s):  
Acoustic Wave ◽  
Electric Field ◽  
Quantum Wells ◽  
Surface Acoustic Wave ◽  
Impact Ionization ◽  
Interface Roughness ◽  
Nonradiative Recombination ◽  
Recombination Centers ◽  
Subsequent Capture ◽  
The Impact

Mechanisms of exciton photoluminescence (PL) quenching in the longitudinal electric field of a standing surface acoustic wave (SAW) have been studied by the example of type II GaAs/AlAs superlattices (SLs). Such SLs with a long lifetime of nonequilibrium carriers have allowed examining the influence of the SAW electric field on the excitonic PL both under the continuous and impulse laser excitations. It has been found that the mechanisms of the interaction of excitons and a SAW electric field depend upon the kinetic energy of excitons and carriers. As for hot excitons and carriers, the standing SAW electric field causes the impact ionization of excitons with a subsequent capture of free carriers at the nonradiative recombination centers, which results in a decrease in the steady-state exciton PL. As for cold excitons and carriers, the impact of excitons with the carriers accelerated by the SAW electric field results mainly in exciton delocalization from the levels of quantum wells formed due to interface roughness with a subsequent capture of excitons at the nonradiative recombination centers, which leads to the acceleration of the PL kinetics.

scholarly journals Numerical simulation of surface acoustic wave actuated cell sorting

2013 ◽  
Vol 11 (4) ◽  
Author(s):  
Thomas Franke ◽  
Ronald Hoppe ◽  
Christopher Linsenmann ◽  
Kidist Zeleke
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Cell Sorting ◽  
Type I ◽  
Type Ii ◽  
Separation Channel ◽  
Carrier Fluid ◽  
A Cell

AbstractWe consider the mathematical modeling and numerical simulation of high throughput sorting of two different types of biological cells (type I and type II) by a biomedical micro-electro-mechanical system (BioMEMS) whose operating behavior relies on surface acoustic wave (SAW) manipulated fluid flow in a microchannel. The BioMEMS consists of a separation channel with three inflow channels for injection of the carrier fluid and the cells, two outflow channels for separation, and an interdigital transducer (IDT) close to the lateral wall of the separation channel for generation of the SAWs. The cells can be distinguished by fluorescence. The inflow velocities are tuned so that without SAW actuation a cell of type I leaves the device through a designated outflow channel. However, if a cell of type II is detected, the IDT is switched on and the SAWs modify the fluid flow so that the cell leaves the separation channel through the other outflow boundary. The motion of a cell in the carrier fluid is modeled by the Finite Element Immersed Boundary method (FE-IB). Numerical results are presented that illustrate the feasibility of the surface acoustic wave actuated cell sorting approach.

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