The resistivity of intrinsic InSb at room temperature is $2 × 10^-4 Ω-cm$. If the mobility of electron is 6 $m^2/V-s$ and mobility of hole is 0.2 $m^2/V-s$. -

Mumbai university > FE > SEM 1 > Applied Physics 1

Marks: 5M

Year: Dec 2013

Given:

$resistivity( ρ ) = 2 × 10^-4 Ωcm$

$μ_e = 6m^2/vs$

$μ_n = 0.2m^2/vs$

To find: intrinsic carrier density(ni)

Soln:

$σ = \frac{1}{ρ}$

$σ = \frac{1}{2 × 10^{-6}}$

$σ = 0.5×10^6$

$σ = n_ie(μ_e + μ_n)$

$n_i = σ/(μ_e + μ_n)$

$= \frac{0.5 × 10^6}{(6 + 0.2) 1.6 × 10^{-19}}$

$ni = 0.05 × 10^{25} kg/m^3$