Pure silicon at 300 K has equal electron (ne) and hole (nh) concentration of 1.5 × 1016 m-3. Doping by indium increases nh to 4.5 × 1022m-3 The ne in the doped silicon is

Question

Pure silicon at 300 K has equal electron (ne) and hole (nh) concentration of 1.5 × 1016 m-3. Doping by indium increases nh to 4.5 × 1022m-3 The ne in the doped silicon is (A) 9 × 105 (B) 5 × 109 (C) 2.25 × 1011 (D) 3 × 1019

Tardigrade Admin · Accepted Answer

In an extrinsic semiconductor nenh =(ni)2 ne × 4.5 × 1022 =(1.5 × 1016)2 ne =(2.25 × 1032/4.5 × 1022) ne =5 × 109

Q. Pure silicon at 300 K has equal electron (n $_{e}$ ) and hole (n $_{h}$ ) concentration of $1.5 \times 1 0^{16} m^{- 3}$ . Doping by indium increases $n_{h}$ to $4.5 \times 1 0^{22} m^{- 3}$ The $n_{e}$ in the doped silicon is

$9 \times 1 0^{5}$

$5 \times 1 0^{9}$

$2.25 \times 1 0^{11}$

$3 \times 1 0^{19}$

In an extrinsic semiconductor
$n_{e} n_{h} = (n_{i})^{2}$
$n_{e} \times 4.5 \times 1 0^{22} = (1.5 \times 1 0^{16})^{2}$
$n_{e} = \frac{2.25 \times 1 0 ^{32}}{4.5 \times 1 0 ^{22}}$
$n_{e} = 5 \times 1 0^{9}$

Q. Pure silicon at 300 K has equal electron (ne​) and hole (nh​) concentration of 1.5×1016m−3. Doping by indium increases nh​ to 4.5×1022m−3 The ne​ in the doped silicon is

9×105

5×109

2.25×1011

3×1019