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High room-temperature hole mobility in $Ge_{0.7 Si_0.3}/Ge/Ge_{0.7}Si_{0.3}$ modulation-doped heterostructures

Madhavi, S and Venkataraman, V (2001) High room-temperature hole mobility in $Ge_{0.7 Si_0.3}/Ge/Ge_{0.7}Si_{0.3}$ modulation-doped heterostructures. In: Journal of Applied Physics, 89 (4). pp. 2497-2499.

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Abstract

Modulation-doped two-dimensional hole gas structures consisting of a strained germanium channel on relaxed $Ge_{0.7}Si_{0.3}$ buffer layers were grown by molecular-beam epitaxy. Sample processing was optimized to substantially reduce the contribution from the parasitic conducting layers. Very high hall mobilities of $1700\hspace{2mm} cm^2/V s$ for holes were observed at 295 K which are the highest reported to date for any kind of p-type silicon-based heterostructures. Hall measurements were carried out from 13 to 300 K to determine the temperature dependence of the mobility and carrier concentration. The carrier concentration at room temperature was $7.9\times10^{11} cm^{-2}$ and decreased by only 26% at 13 K, indicating very little parallel conduction. The high-temperature mobility obeys a $T^{-\alpha}$ behavior with $\alpha$~2, which can be attributed to intraband optical phonon scattering.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to American Institute of Physics.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 19 Jan 2007
Last Modified: 19 Sep 2010 04:29
URI: http://eprints.iisc.ernet.in/id/eprint/7610

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