1. When P and N extrinsic semiconductors
are formed as a PN-junction, the diffusion of holes from P-side to N-side and
diffusion of electrons from N-side to P-side occurs
2.
The
region of P and N materials near the junction are depleted of charges. So, immobile ions are left over.
3.
I0
is the reverse saturation current in reverse bias condition.
4.
I0
is doubles for every 100 rise for germanium and for every 60
rise in silicon.
5.
Reverse
saturation current is a micro-amphers for
germanium & nano -ampheres in silicon diodes
6.
Practically
Barrier Potential Is 0.5 To 1 Micron (106).
7.
Barrier
potential width is depends is depends on the temperature .when temperature
increases potential barrier width is decreased.
9.
Generally
potential barrier potential voltage is 0.3v for germanium 0.7v for silicon
Ø
Saturation
Current I= I0(E‑V/Nvt - 1 ).
Ø Channel length modulation does not exist
in pn-junction diode. This is for only in MOSFETS.
Barrier Potential Is Depends On The Following
o
Type
Of Semi-Conductor
o
Donor
Impurity Added
o
Acceptor
Impurity Added
o
Temperature
Mainly PN-Junction Diode Having Two Types Of
Resistance
o
Static
Resistance (Dc Condition )
o
Dynamic
Resistance (Ac Condition)
Static Resistence of PN-Junction
Diode:
Static Resistance Is Measured In Dc Condition.
In Dc Condition Resistance is Zero Means It Is In Short Circuit
Dynamic Resistance of PN-Junction
Diode:
It Is Defined As The Reciprocal Of Slope Of Forward Characteristics.
Typically It’s Value Is 1-25ohms
Ø
In
Reverse Bias Condition Resistance Of Diode Is Infinity Because This Is Open Ckt
Condition.
Ø Reverse Break-Down Voltage Of Silicon
Is Higher Than The Germanium Diode
Important Formulas In Pn-Junction Diode
Vt = K
* T
K=8.62*10-5ev/0k
T=Temp (At Room T= 27 + 273= 3000k)
When They Give One Saturation Current
And Two Temperature Values We Can Find Another Saturation Current Through This
Formulae i.e
I02 = I01 (2t2-T1/
10)