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How does the resistivity of an extrinsic germanium sample change with temperature

  1. Jul 1, 2011 #1
    We have an experiment of the students to calculate the resistivity of an extrinsic (p or n) Germanium sample using Four Probe method at different temperatures (the sample is heated from room temperature and the voltage and current are measured for increasing temperature and then the same is done during the cooling if the sample).

    In the aim of the experiment is mentioned to heat the Ge sample to maximum 200 C. I remember during my college days a teacher of ours mentioned that the Ge sample should not be heated above 80 C as above that the extrinsic Ge will become intrinsic.

    I know that the max operating junction temp of a Ge device is 80 C and for a Si its about 150 C but i can't seem to relate to the extrinsic Ge converting to intrinsic Ge above 80 C (why did they mention the max temp. as 200 C in the aim)

    Any one have any idea about this?
  2. jcsd
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