A battery of emf 2 V is applied across the block of a semiconductor. The length of the block is 0.1 m and the area of cross-section is `1xx10^(-4)m^2`. If the block is of intrinsic silicon at 300K, find the electron and hole currents a) What will be the magnitude of the total current? b) What will be the magnitude of the total current if germanium is used instead of silicon
Given : `{:(" ","For Si at 300 K","For Ge at at 300K"),(mu_e,0.135m^2V^(-1)S^(-1),0.39m^2V^(-1)s^(-1)),(mu_h,0.048m^2V^(-1)s^(-1),0.19m^2V^(-1)s^(-1)),(n_i,1.5xx10^(16)m^(-3),2.4xx10^(19)m^(-3)):}`

Explanation

For silicion, Electron current, `I_e=(n_eAemu_eV)/l`
`=(1.5xx10^(16)xx10^(-4)xx1.6xx10^(-19)xx0.135xx2)/(0.1)=6.48xx10^(-7)A`
Hole current, `I_h=(n_hAemu_hV)/l=(1.5xx10^(16)xx10^(-4)xx1.6xx10^(-19)xx0.048xx2)/(0.1)=2.30xx10^(-7)A`
(a) Total current, `I=I_e+I_h=(6.48+2.30)xx10^(-7)A=8.78xx10^(-7)A`
(b) Similarly for germanium, Electron current, `I_e=2.995xx10^(-3)A`
and hole current, `I_h=1.459xx10^(-3)A` (use the data for germanium)
Total current, `I=I_e+I_h=4.454xx10^(-3)A`