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Question

The I-V characteristics of three types of diodes at the room temperature, made of semiconductors X, Y and Z, are shown in the figure. Assume that the diodes are uniformly doped and identical in all respects except their materials. If $E_{gX}$, $E_{gY}$ and $E_{gZ}$ are the band gaps of X, Y and Z, respectively, then

The correct answer is

$E_{gX} < E_{gY} < E_{gZ}$

The problem involves understanding the relationship between the band gap energy of semiconductors and the forward voltage drop (threshold voltage) observed in diode characteristics.

For a semiconductor diode, the forward voltage drop (threshold voltage) is related to the band gap energy (\(E_g\)) of the material. Generally, the larger the band gap, the higher the threshold voltage required for current conduction. This is because a larger band gap implies that the material requires more energy to move electrons from the valence band to the conduction band.

In the given diagram, we have three diodes made from semiconductors X, Y, and Z, each with distinct I-V characteristics. Analysis of the graph shows:

  • Diode X has the least forward voltage drop.
  • Diode Y has a moderate forward voltage drop.
  • Diode Z has the highest forward voltage drop.

This suggests that:

  • \(E_{gX}\) is the smallest because Diode X conducts at the lowest voltage.
  • \(E_{gY}\) is greater than \(E_{gX}\) but less than \(E_{gZ}\).
  • \(E_{gZ}\) is the largest as it requires the highest voltage for conduction.

Thus, the correct relationship among the band gaps is:

\(E_{gX} < E_{gY} < E_{gZ}\)

Therefore, the correct answer is: \(E_{gX} < E_{gY} < E_{gZ}\)

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Important Questions from Energy Band Gap

  1. Which among the following represents the energy level of quantum Dot ?
  2. Arrange the following in descending orders of Energy gaps of semiconductor Materials.

    A. Si

    B. Ge

    C. GaAs

    D. GaP

    Choose the correct answer from the options given below :

  3. Following are semiconductor materials arrange them in ascending order of their band gaps :

    (a) Si

    (b) Ge

    (c) Ga N

    (d) Ga As

    The correct sequence in ascending order is given by

  4. Following semiconductor materials are given :

    (a) Si  

     (b) Ge   

    (c) GaP  

     (d) GaAs

    Arrange them in ascending order of their band gap. The correct option is :

  5. An electron in the conduction band

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