Question

a) In a Gunn diode oscillator, the electron drift velocity was found to be 10⁷ cm/sec and the critical field for GaAs as 3.2 KV/cm. If the effective length is 20 microns, determine the

i. Intrinsic frequency

ii. Critical voltage that can be applied to the diode.

Answer 1

Given

Drift Velocity (Vd) = 10⁷ cm/sec

The critical field for GaAs = 3.2 KV/cm

Effective length (L) = 20 microns

Solution

Part 1

Intrinsic Frequency = (Drift Velocity/Effective length)

= Vd/L

= 10⁷ / 2010^-4 cm   

= 10⁷ 10⁴ /20 sec^-1

= 10¹¹/20 Hz

= 5 10⁹ Hz

Hence Intrinsic Frequency = 5 GHz ------>> answer

Part 2

Critical Voltage (V) = (Critical Field of GaAs Effective Length) V

= 3.2 KV/cm 20 10^-4 cm

= 3.2 10³ 20 10^-4 Volts

= 6.4 Volts

Hence Critical Voltage (V) = 6.4 Volts ------> answer