logo

CuriousTab

CuriousTab

Discussion


Home Electronics Semiconductor Principles See What Others Are Saying!
  • Question
  • In "p" type material, minority carriers would be:


  • Options
  • A. holes
  • B. dopants
  • C. slower
  • D. electrons

  • Correct Answer
  • electrons 

    Explanation
    The purpose of p-type doping is to create an abundance of holes. In the case of silicon, a trivalent atom (typically from Group 13 of the periodic table, such as boron or aluminium) is substituted into the crystal lattice. The result is that one electron is missing from one of the four covalent bonds normal for the silicon lattice. Thus the dopant atom can accept an electron from a neighboring atom's covalent bond to complete the fourth bond. This is why such dopants are called acceptors. The dopant atom accepts an electron, causing the loss of half of one bond from the neighboring atom and resulting in the formation of a "hole". Each hole is associated with a nearby negatively charged dopant ion, and the semiconductor remains electrically neutral as a whole. However, once each hole has wandered away into the lattice, one proton in the atom at the hole's location will be "exposed" and no longer cancelled by an electron. This atom will have 3 electrons and 1 hole surrounding a particular nucleus with 4 protons. For this reason a hole behaves as a positive charge. When a sufficiently large number of acceptor atoms are added, the holes greatly outnumber thermal excited electrons. Thus, holes are the majority carriers, while electrons become minority carriers in p-type materials.

  • More questions

    • 1. A single-phase induction motor

    • Options
    • A. is self-starting
    • B. operates at a fixed speed
    • C. is less reliable than a three-phase synchronous motor
    • D. none of the above
    • Discuss
    • 2. Series resonance happens when _____.

    • Options
    • A. XC = XC
    • B. XL = XC
    • C. XL = XB
    • D. XT = R
    • Discuss
    • 3. In this analog amplifier the input is in phase with the output.


    • Options
    • A. True
    • B. False
    • Discuss
    • 4. The double-inversion rule states that if a variable is inverted twice, then the variable will be back to its original state.

    • Options
    • A. True
    • B. False
    • Discuss
    • 5. A triangular-wave oscillator can consist of an op-amp comparator, followed by a(n)

    • Options
    • A. differentiator
    • B. amplifier
    • C. integrator
    • D. multivibrator
    • Discuss
    • 6. The number of joules used in 1 second is always equal to the number of _______.

    • Options
    • A. siemens
    • B. coulombs
    • C. amperes
    • D. watts
    • Discuss
    • 7. A virtual ground is a(n) ______ ground because this point is at zero volts.

    • Options
    • A. ordinary
    • B. voltage
    • C. chassis
    • D. earth
    • Discuss
    • 8. The basic instrumentation amplifier has ________ input(s).

    • Options
    • A. 1
    • B. 2
    • C. capacitive
    • D. resistive
    • Discuss
    • 9. What is the total current?


    • Options
    • A. 15.6 mA
    • B. 17.8 mA
    • C. 21.9 mA
    • D. 26.0 mA
    • Discuss
    • 10. This circuit is a low-pass filter.


    • Options
    • A. True
    • B. False
    • Discuss


    Comments

    There are no comments.

Enter a new Comment