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      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/032/01/0109-0115

    • Keywords

       

      Mixed; semiconductors; co-precipitation; optical characterization; thermoelectric power.

    • Abstract

       

      The polycrystalline Pb𝑥Zn1–𝑥S semiconductor powder with (0 ≤ 𝑥 ≤ 0.5) has been prepared by controlled co-precipitation method from an alkaline medium using thiourea as a sulphide ion source. Pellets are made with these powders applying 10 ton/sq.cm. pressure and sintered at 800°C for 2 h in nitrogen atmosphere. X-ray studies of these samples have indicated that the compounds are polycrystalline in nature with mixed hexagonal and cubic structure of ZnS and cubic structure of PbS. Lattice parameters (𝑎 and 𝑐) of all the compounds are determined from the X-ray data and are found to decrease nonlinearly with increase in Pb concentration (𝑥). It is also observed that the grain size of the crystallites increases in samples with 𝑥 = 0–0.5. Scanning electron micrographs have shown that both cubic and hexagonal crystallites are present in the mixed crystals. The electrical conductivity in Pb𝑥Zn1–𝑥S is found to decrease with increase in composition (𝑥 = 0–0.5), whereas it increases at all temperatures in all samples. Mobility of charge carrier concentration is found to increase with increasing temperature. The increase in carrier mobility in Pb𝑥Zn1–𝑥S samples may be due to reduced grain boundary potential. In Pb𝑥Zn1–𝑥S samples with 𝑥 = 0–0.3, the sum of the activation energy due to charge carriers and grain boundary potential is equal to the activation energy due to conductivity.

    • Author Affiliations

       

      M Nagabhushanam1 E Nagabushan2 D Jaya Prakash2 B Rajam2 K Yadaiah3

      1. Department of Physics, University College of Science, Osmania University, Hyderabad 500 007, India
      2. University College of Technology, Osmania University, Hyderabad 500 007, India
      3. S.V. Degree and P.G. College, Suryapeta, Nalagonda (Dist) 508 213, India

    • Dates

       
      Published
      February 2009
      Manuscript received
      1 May 2008

  • Bulletin of Materials Science | News

    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

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      Posted on July 25, 2019

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