The electron concentration in Silicon is n0 3 times 104 cm3

The electron concentration in Silicon is n_0 = 3 times 10^4 cm^-3. (a) Determine p_0. (b) Is this material n or p type? (c) Determine E_F - E_ nu (T = 300K)

Solution

1.) Determine P₀ ?

Ans: Expression: P_{0 =} n_i² / n₀

Where P_{0 =} thermal-equilibrium concentration of holes

            n_i =intrinsic carrier concentration, which refers to either the intrinsic electron or hole concentration,

                   At T=300K, silicon n_{i =} 1.5 x 10¹⁰ cm^-3

                  n₀ =thermal-equilibrium concentration of electrons, given, 3 x 10⁴ cm^-3

Now substitute the following values = P_{0 =} n_i² / n₀ = (1.5 x 10¹⁰ cm^-3)² / 3 x 10⁴ cm^-3

= 0.75 x 10¹⁶ cm^-3

2.) Is material n or p type?

Ans: Since thermal equilibrium concentration of electrons n₀ = 3 x 10⁴cm^-3is more than P_{0 =}0.75 x 10¹⁶ cm^-3

so it is of n-type semiconductor

3.) Determine E_F- E_V  (T=300K)

Ans: E_F- Ev = kT ln(N_v/ P)

         Where KT = 0.026 where T=300K

                     P = 0.75 x 10¹⁶ cm^-3

                     N_v = 1.04 × 10¹⁹ cm^-3 of silicon            

E_F - E_v = 0.026 x ln (1.04 × 10¹⁹ cm^-3 / 0.75 x 10¹⁶ cm^-3 )

           = 0.026 x ln (0.721154 x 10³)

           = 0.026 x ln (721.15)

           = 0.026 x 6.58084716

           = 0.171102