Concepts Of Physics MCQ Edition [Volume 2]

Exam: Concepts Of Physics MCQ Edition [Volume 2]
Subject: Physics
Chapter: Semiconductors and Semiconductor Devices

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Semiconductors and Semiconductor Devices

When a semiconducting material is doped with an impurity, new...

When a semiconducting material is doped with an impurity, new acceptor levels are generated. During a specific thermal collision, a valence electron gains an energy equal to

2kT

, just reaching one of the acceptor levels. Assuming the initial energy of the electron was at the top edge of the valence band and the temperature

T

300 \text{ K}

, determine the energy of the acceptor levels above the valence band.

Options

A $103.4 \text{ meV}$
B $51.7 \text{ meV}$
C $25.8 \text{ meV}$
D $50.0 \text{ meV}$

Correct answer

B. $51.7 \text{ meV}$

Step-by-step solution

The energy required for the electron to reach the acceptor level from the top of the valence band is given as

\Delta E = 2kT

.

Substituting the value of the Boltzmann constant

k = 8.62 \times 10^{-5} \text{ eV/K}

and temperature

T = 300 \text{ K}

\Delta E = 2 \times 8.62 \times 10^{-5} \times 300

\Delta E = 51.72 \times 10^{-3} \text{ eV}

\Delta E \approx 51.7 \text{ meV}

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