CARRIER TYPE REVERSAL IN $Pb_{x}Ge_{42-x}Se_{58}$ AND $Pb_{20}Ge_{y}Se_{80-y}$ GLASSES EXHIBITED IN THERMAL DIFFUSIVITY MEASUREMENTS

Ganesan, R and Thangaraju, B and Sangunni, KS and Gopal, ESR (2001) CARRIER TYPE REVERSAL IN $Pb_{x}Ge_{42-x}Se_{58}$ AND $Pb_{20}Ge_{y}Se_{80-y}$ GLASSES EXHIBITED IN THERMAL DIFFUSIVITY MEASUREMENTS. In: Journal of Optoelectronics and Advanced Materials, 3 (2). pp. 467-472.

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Abstract

Bulk $Pb_{x}Ge_{42-x}$ (x= 0, 2.5, 5, 7.5, 9, 10 & 15 at.%) and $Pb_{20}Ge_{y}Se_{80-y}$ (y = 17, 19, 21, 23and 25 at.%) homogeneous glasses have been prepared by melt quenching. The thermal diffusivity has been measured by the photoacoustic technique using a laboratory built non-resonant photoacoustic cell. The composition dependence of thermal diffusivity shows an anomalous behavior at x= 9 at% of Pb in $Pb_{x}Ge_{42-x}$ and y = 21at.% of Ge in $Pb_{20}Ge_{y}Se_{80-y}$glasses, the composition at which a p- to n- conduction transition generally occurs. The reported electrical conductivity and optical band gap measurements are used to explain the minimum thermal diffusivity value obtained at the transition threshold in these glasses. These results have been explained with the Kolobov model on the basis of modification of the charged defect states due to the addition of metallic elements.

Item Type:	Journal Article
Publication:	Journal of Optoelectronics and Advanced Materials
Publisher:	Journal of Optoelectronics and Advanced Materials
Additional Information:	Copyright belongs to Journal of Optoelectronics and Advanced Materials
Keywords:	Disordered systems;Semiconductors;Thermodynamic
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	15 Dec 2008 10:16
Last Modified:	19 Sep 2010 04:53
URI:	http://eprints.iisc.ac.in/id/eprint/16626

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