Physics for Information Science: Unit II: Semiconductor Physics
Determination of Band Gap Energy
Intrinsic Semiconductors
We know for intrinsic semiconductor σi = Ce -Eg/2KBT. where C is a constant.
DETERMINATION
OF BAND GAP ENERGY
We
know for intrinsic semiconductor σi = Ce -Eg/2KBT
where
C is a constant.
We
know resistivity ρi = 1/
Conductivity
ρi
= 1/C e Eg/2KBT ………(1)
We
know resistivity is resistance per unit area per unit length
(i.e.)
ρi = Ri a/Ɩ ………(2)
where,
ρi → Resistance
a→
Cross sectional area
Ɩ → Length
Equating
equations (1) and (2) we get,
Taking
log on both sides 
In
general we can write 
The
resistance can be found using meter bridge or carey fosters bridge or post
office box experiments at various temperatures.
If
a graph is plotted between 1/T and log Ri a straight line is
obtained as shown in Fig. 2.11, with a slope
Therefore by finding the slope of line we can calculate the energy band gap Eg with the following expression.
Eg=2KB
(dy/dx) Joules
Physics for Information Science: Unit II: Semiconductor Physics : Tag: : Intrinsic Semiconductors - Determination of Band Gap Energy
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PH3256 2nd Semester CSE Dept | 2021 Regulation | 2nd Semester CSE Dept 2021 Regulation