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Your search keyword '"Yakimov, Andrew I."' showing total 5 results
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5 results on '"Yakimov, Andrew I."'

1. AC-Hopping Conductance of Self-Organized Ge/Si Quantum Dot Arrays

Author

Drichko, Irina L., Diakonov, Andrey M., Kozub, Veniamin I., Smirnov, Ivan Yu., Galperin, Yuri M., Yakimov, Andrew I., and Nikiforov, Alexander I.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Dense ($n=4 \times 10^{11}$ cm$^{-2}$) arrays of Ge quantum dots in Si host were studied using attenuation of surface acoustic waves (SAWs) propagating along the surface of a piezoelectric crystal located near the sample. The SAW magneto-attenuation coefficient, $\Delta\Gamma=\Gamma(\omega, H)-\Gamma(\omega, 0)$, and change of velocity of SAW, $\Delta V /V=(V(H)-V(0)) / V(0)$, were measured in the temperature interval $T$ = 1.5-4.2 K as a function of magnetic field $H$ up to 6 T for the waves in the frequency range $f$ = 30-300 MHz. Basing on the dependences of $\Delta\Gamma$ on $H$, $T$ and $\omega$, as well as on its sign, we believe that the AC conduction mechanism is a combination of diffusion at the mobility edge with hopping between localized states at the Fermi level. The measured magnetic field dependence of the SAW attenuation is discussed basing on existing theoretical concepts., Comment: 4 pages, 6 figures

Published
2003

2. Angle-Selective Photodetection in Ge/Si Quantum Dot Photodiodes Enhanced by Microstructured Hole Arrays.

Author

Yakimov, Andrew I., Kirienko, Victor V., Bloshkin, Aleksei A., Utkin, Dmitrii E., and Dvurechenskii, Anatoly V.

Subjects
PHOTOTHERMAL effect, QUANTUM dots, POYNTING theorem, PHOTODIODES, ELECTRIC fields, RESONANCE, RADIATION
Abstract

We report on the near-infrared (NIR) photoresponse of a micropatterned Ge/Si quantum dot (QD) pin photodiode at different angles of radiation incidence. The photon-trapping hole array was etched through the n+-type top contact layer to reach the buried QDs. The normal-incidence responsivity was observed to be resonantly increased at wavelengths of 1.4, 1.7, and 1.9 μ m by factors of 40, 33, and 30, respectively, compared with the reference detector without holes. As the incident angle θ increases, the resonance peaks are disappeared and at θ > 40 ∘ a new resonance with a 25 × enhancement arises at a wavelength of 1.8 μ m. Simulation of the near-field intensity, Poynting vector distribution and wave polarization showed that at small θ , the strong electric field is primarily localized under the air holes (1.4 μ m, TM mode) or between the holes (1.7 and 1.9 μ m, TE modes) inside the region occupied by QDs, resulting in the strong NIR photocurrent. At large θ , the dominant resonance detected at 1.8 μ m is the result of coupling between the TE and TM modes and formation of a mixed near-field state. [ABSTRACT FROM AUTHOR]

Published
2023
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