FREE CARRIER MICROWAVE SEMICONDUCTOR DEVICES.
Semi-Annual rept. no. 4, 15 Jan-15 Jul 66,
GENERAL TELEPHONE AND ELECTRONICS LABS INC BAYSIDE NY BAYSIDE LAB
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A small signal analysis is presented by the bulk terminal impedance of a CdS bar in which the drifting charge carriers and vibrating lattice interact via the piezoelectric coupling. It was shown through a sample calculation that for practical ranges of applied drift voltage, material parameters, and semiconductor dimensions a negative real part to the terminal impedance could be achieved at room temperatures. The magnitude of this negative real part of the terminal impedance makes possible the design of practical bulk amplifiers and oscillators in 50 ohm TEM mode transmission line. Experiments on low resistivity semiconducting CdS indicate that acoustoelectric interaction takes place in the crystal for applied pulse drift electric fields above a threshold field corresponding to the synchronous carrier velocity. Microwave measurements show that rf radiation emanates from the bulk CdS sample and is associated with the acousto-electric interaction. It was observed that radiation occurs both during the period of domain travel in the sample and during the time of domain collapse at the anode. Using optical probe techniques, the spectrum of the acoustic lattice waves in CdS under conditions of high pulsed electric field has been measured. It was determined that the spectrum exhibited a peak amplitude at one frequency and that this frequency was determined by the nature of the acoustic pulse nucleation site. Author
- Electrical and Electronic Equipment
- Solid State Physics