Question

Find the current produced at room temperature in a pure germanium plate of area `2 xx 10^(-4) m^(2)` and of thickness `1.2 xx 10^(-3) m` when a potential of `5 V` is applied across the faces. Concentration of carries in germanium at room temperature is `1.6 xx 10^(6)` per cubic metre. The mobilities of electrons and holes are `0.4 m^(2) V^(-1) s^(-1)` and `0.2 m^(2) V^(-1) s^(-1)` respectively. The heat energy generated in the plate in `100` second is.

Answer 1

conductivity of a semiconductor
`sigma=n_(e)emu_(e)+n_(h)emu_(h)`
Since semiconductor is intrinsic
`n_(e)=n_(h)=n_(i)`
`sigma=n_(i)e(mu_(e)+mu_(h))`
`=1.6xx10^(6)xx1.6xx10^(-19)(0.4+0.2)`
`=1.536xx10^(-13)ohm^(-1)m^(-1)`
`i=jA=sigmaEA=sigma((V)/(d))A`
`=1.536xx10^(-13)((5)/(1.2xx10^-(3)))(2xx10^(-4))`
`=1.28xx10^(-13)A`
`H=Vit`
`=5xx1.28xx10^(-13)xx100`
? `=6.4xx10^(-11)J`