Semiconducting Devices Question 51
Question: A potential difference of 2V is applied between the opposite faces of a Ge crystal plate of area 1 cm2 and thickness 0.5 mm. If the concentration of electrons in Ge is 2 x 10 ^${-19}$/m3 and mobilities of electrons and holes are $ 0.36\frac{m^{2}}{volt-\sec } $ and $ 0.14\frac{m^{2}}{volt-\sec } $ respectively, then the current flowing through the plate will be
Options:
A) 0.25 A
B) 0.45 A
C) 0.56 A
D) 0.64 A
Show Answer
Answer:
Correct Answer: D
Solution:
$ \sigma =ne({\mu _{e}}+{\mu _{h}})=2\times 10^{19}\times 1.6\times {{10}^{-19}}(0.36+0.14) $
$ =1.6{{(\Omega \text{-}m)}^{-1}} $
$ R=\rho \frac{l}{A}=\frac{l}{\sigma A}=\frac{0.5\times {{10}^{-3}}}{1.6\times {{10}^{-4}}}=\frac{25}{8}\Omega $
$ i=\frac{V}{R}=\frac{2}{25/8}=\frac{16}{25}A=0.64A $
