The product of the conduction electron concentration and the hole concentration remains independent of the quantity of any doped impurity. In pure germanium, the concentration of conduction electrons is 6 × 10^ 19 per

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Correct answer: B. 1.8 × 10^ 16 per cubic metre

In an intrinsic semiconductor, the concentration of conduction electrons is equal to the concentration of holes, which is the intrinsic carrier concentration

n_i

.

Given

n_i = 6 \times 10^{19} \text{ m}^{-3}

.

According to the mass action law, the product of electron and hole concentrations remains constant at a given temperature:

n_e n_h = n_i^2

After doping, the new electron concentration is

n_e = 2 \times 10^{23} \text{ m}^{-3}

.

Substituting the values into the mass action law:

n_h = \dfrac{n_i^2}{n_e} = \dfrac{(6 \times 10^{19})^2}{2 \times 10^{23}}

n_h = \dfrac{36 \times 10^{38}}{2 \times 10^{23}}

n_h = 18 \times 10^{15} = 1.8 \times 10^{16} \text{ m}^{-3}

The product of the conduction electron concentration and the hole...

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