Question

AIIMS 2013
41. Given that the mobility of electrons in Ge is
0.4 metre square/volt seo and electronic charge is
1.6 x10-19C. How many donor atom (per m^3 have
in semiconductor of conductivity 500 mho/m
D 8 x 1021
(2) 8 x 1015
(3) 5 x 1021
(3) 8 x 1016
​

Answer 1

Answer:

Using, σ=n

e

qμ

e

Here, σ=500 mho/m

e=1.6×10

−19

C

μ

r

=0.4m

2

V

−1

s

−1

∴n

e

=

1.6×10

−19

×0.4

500

=7.8×10

21

=8×10

21

m

−3