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Flicker noise in degenerately doped Si single crystals near the metal-insulator transition

Raychaudhuri, AK and Ghosh, Arindam and Kar, Swastik (2002) Flicker noise in degenerately doped Si single crystals near the metal-insulator transition. In: Pramana-Journal of Physics, 58 (2). pp. 343-359.


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In this paper we report some of the important results of experimental investigations of the flicker noise near the metal--insulator (MI) transition in doped silicon single crystals. This is the first comprehensive work to study low-frequency noise in heavily doped Si over an extensive temperature range (2 K < T < 500 K). The measurements of conductance fluctuations (flicker noise) were carried out in the frequency range $10^{-2}<f<4\times10^1$ Hz in single crystalline Si across the MI transition by doping with phosphorous and boron. The magnitude of noise in heavily doped Si is much larger than that seen in lightly doped Si over the whole temperature range. The extensive temperature range covered allowed us to detect two distinct noise mechanisms. At low temperatures (T < 100 K) universal conductance fluctuations (UCF) dominate and the spectral dependence of the noise is determined by dephasing the electron from defects with two-levels (TLS). At higher temperatures (T > 200 K) the noise arises from activated defect dynamics. As the MI transition is approached, the 1/f spectral power, typical of the metallic regime, gets modified by the presence of discrete Lorentzians which arise from generation-recombination process which is the characteristic of a semiconductor.

Item Type: Journal Article
Publication: Pramana-Journal of Physics
Publisher: Indian Academic of Sciences
Additional Information: Copyright of this article belongs to Indian Academic of Sciences.
Keywords: 1/f noise;Doped Si;MI transition.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 03 Jun 2006
Last Modified: 19 Sep 2010 04:28
URI: http://eprints.iisc.ac.in/id/eprint/7439

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