Calculating carrier concentration in an intrinsic semiconductor — an example. Let us work out the carrier concentration in an intrinsic semiconductor, say germanium, at 400 K . For germanium at 300 K (see Table I): N
c
= 1.02 * 10
19
cm
– 3
; N
v
= 5.65 * 10
18
cm
– 3
; and E
g
= 0.66 eV .
How do you calculate carrier concentration?
The product of the majority and minority carrier concentration at equilibrium is a constant, which is mathematically expressed by the Law of Mass Action.
n
o
p
o =
n
i
2
where n
i
: is the intrinsic carrier concentration n
0
: electron equilibrium carrier concentrations.
What is the intrinsic carrier concentration of germanium?
| Energy gap 0.661 eV | Intrinsic carrier concentration 2.0·10 13 cm – 3 | Intrinsic resistivity 46 Ω·cm | Effective conduction band density of states 1.0·10 19 cm – 3 | Effective valence band density of states 5.0·10 18 cm – 3 |
|---|
What is the carrier concentration of an intrinsic semiconductor?
The intrinsic carrier concentration is
the number of electrons in the conduction band or the number of holes in the valence band in intrinsic material
. This number of carriers depends on the band gap of the material and on the temperature of the material.
How do you calculate intrinsic carrier concentration?
The intrinsic carrier concentration is assumed to be
ni = 1.5 x 1010 cm-3
.
How do you calculate intrinsic carrier concentration at different temperatures?
You can also use our calculator in Advanced mode to get a more realistic value of the intrinsic carrier concentration in silicon at different temperatures. The Advanced mode uses the empirical formula proposed by Misiakos and Tsamakis:
N
i
= 5.29 * 10
19
* (T / 300)
2.54
* exp(-6726 / T)
.
Why is NP NI 2?
p-type doping moves the fermi level close to the valence band, n-type doping moves it closer to the conduction band. If the product of the concentrations doesn’t change based on what the fermi level is, then the mass action law doesn’t care how you dope it. np = ni
2
regardless of doping
.
What is the unit of carrier concentration?
Charge carrier density, also known as carrier concentration, denotes the number of charge carriers in per volume. In SI units, it is measured in
m
− 3
.
What is meant by carrier concentration?
The intrinsic carrier concentration is
the number of electrons in the conduction band or the number of holes in the valence band in intrinsic material
. This number of carriers depends on the band gap of the material and on the temperature of the material.
What is the concentration of holes?
In a similar way, at room temperature or elevated temperatures, each acceptor creates one hole in the valence band, and the hole concentration, p, in the valence band of a p-type semiconductor is
approximately equal to the acceptor concentration
, N
a
.
Why does the intrinsic carrier concentration change with temperature?
The thermal excitation of a carrier from the valence band to the conduction band creates free carriers in both bands. … Alternatively,
increasing the temperature makes it more likely that an electron will be excited into the conduction band
, which will increase the intrinsic carrier concentration.
Why intrinsic carrier concentration is constant?
Ns increases with temperature because higher states in the conduction band, and deeper states in the valence band, become more accessible as the thermal energy increases. However, around room temperature it is not bad to regard Ns as a constant, because
the dominant T dependence in eq
.
What is the intrinsic carrier concentration of silicon at room temperature?
1. A silicon sample at room temperature has an intrinsic carrier concentration of
ni = 5×109 cm-3
.
What is intrinsic concentration of silicon?
The intrinsic carrier concentration varies between materials and is dependent on temperature. Silicon’s n
i
, for example, is
roughly 1.08×10
10
cm
− 3
at 300 kelvins
, about room temperature. In general, increased doping leads to increased conductivity due to the higher concentration of carriers.
How does the carrier concentration in intrinsic semi conductors depend on temperature?
This number of carriers depends on
the band gap of the material and on the temperature of the material
. … Alternatively, increasing the temperature makes it more likely that an electron will be excited into the conduction band, which will increase the intrinsic carrier concentration.
How do you calculate intrinsic Fermi level?
At temperature T K, the electron concentration ‘n’ is equal to hole concentration ‘p’ in an intrinsic semiconductor i.e.,
n = p
. Hence Fermi level lies in middle of Energy band gap.
