Question

Mobility of electron and hole in a sample of Ge at room temperature are 0.36 m² /V-sec and 0.17m² /V-sec respectively. If electron and holes densities are equal and it is 2.5 ×10¹³ /cm³ , calculate its conductivity.

Answer 1

Data :- μ_e  = 0.36 m² /V-sec  μ_h  = 0.17m² /V-sec  T =300°K

             `n_i = 2.5×10^13/(cm^3 )  = 2.5×10^19m^3`

Formula :- σ = n(μ_e- μ_h). e 
Calculations :- σ = 2.5×10¹⁹(0.36 + 0.17)×1.6×10^-19 

                          = 2.12 mho/metre
Answer :- σ = conductivity = 2.12 mho/metre.