SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

4.8. DIODE APPLICATIONS: AN OVERVIEW 183

(Zener diode)

p n

Vo

I

I

V

Forward current

Reverse

saturation

current

Vout=Vz

Reverse

current = (Vo – Vz)/RL

Vz

RL

Figure 4.23: (a) Tunneling breakdown effect in the reverse-biasedp-ndiode for a voltage-
clamping circuit. The circuit is thus very useful as a voltage regulator and zener diode circuit
symbol.

The breakdown for diamond is

VBD(C) = 51. 7 ×

(

107

4 × 105

) 2

=32.3kV!

One can see the tremendous potential of diamond for high-power applications where the

device must operate under high applied potentials. At present, however, diamond-based

diodes are not commercially available.

4.8 DIODEAPPLICATIONS:ANOVERVIEW....................

4.8.1 Applications of p-n diodes .........................

The p-n junction (or the Schottky diode) is the fundamental building block of semiconductor
devices. The applications are based on certain properties of the junction

I. The injection of electron-hole pairs to generate light via recombination (eg. LEDs and

LASERs)

II. The separation of electron-hole pairs at the junction to constitute a current source (eg.

solar cell)

III. The temperature dependence of the I-V characteristic (eg. a temperature sensor)

IV. The non-linear nature of the I-V characteristic (eg. frequency multipliers and mixers)

V. The device as a switch (eg. rectifiers, inverters, power supplies etc)