Abstract :
When the surface of a semiconductor is bombarded by an electron beam, hole-electron pairs are generated in the semiconductor. By choosing a suitable geometry. for a p-n junction with respect to the bombarded surface, a substantial number of the hole-electron pairs are collected by the junction and a current is thus induced. The magnitude of the induced current depends on the incident electron beam current, the accelerating voltage, and the junction bias. For accelerating voltages of 16 kv, induced currents with magnitudes several thousand times greater than the beam currents have been measured. The effect may be used as a high-speed switch in connection with electronic commutation where the back resistance of the junction is modulated by the action of the bombarding electron beam. Such switching action has been demonstrated with rise times less than 0.1 µsec and decay times of the order of microseconds. With the help of special semiconductor designs, various other potential applications utilizing this effect are possible. These include the use of the element as an 1) amplifier, 2) oscillator, 3) frequency multiplier, and 4) rectifier. The design criteria relating to such cases is indicated.
