SOLID STATE LIGHT EMITTING DIODE WHEREIN OUTPUT IS CONTROLLED BY CONTROLLING ELECTION POPULATION OF AN INTERMEDIATE LEVEL WITH AN AUXILIARY LIGHT SOURCE

摘要

A controlled P-N recombination-radiation source is caused to emit radiation upon the simultaneous application of (a) a controlling radiation and (b) an electric signal; the controlling radiation may be supplied by a further P-N recombination-radiation junction, and the emitted radiation may be detected in a photo-conductor; the whole may be assembled to provide an "AND" solid-state opto-electronic circuit element. In an embodiment, the controlled source is a gallium or aluminium phosphide P-N junction, doped with oxygen and zinc; the controlling radiation is of wavelength 9, 100 rA from a doped gallium arsenide or indium or aluminium phosphide body, and the emitted radiation is of wavelength 7000 rA. The effect of the controlling radiation may be to saturate an intermediate level and thus prevent radiative recombination; alternatively, the controlled source may be doped with iron or cobalt, and will not emit radiation until the radiationless recombination centres thus introduced are saturated by the controlling radiation, i.e. the sources will have a super-linear emission above a threshold. The photo-conductor may also comprise a P-N junction, e.g. of gallium phosphide doped with zinc and oxygen. Direct activation of the photo-conductor by the controlling source may be prevented either by making the energy quanta of the controlling radiation smaller than the quanta required to activate the photo-conductor, or by incorporating reflective layers between the various sources. The controlling source may be made by alloying a tin contact at 400-700 DEG C. for less than one second, producing a recrystallized N-type region in a P-type gallium phosphide body, and simultaneously forming an ohmic contact of gold containing 4 weight per cent zinc, or by diffusing zinc at 900 DEG C. into N-type gallium arsenide, using tin and indium-zinc contacts. The controlled source may be formed by diffusing zinc at 800 DEG C. into an N-type gallium phosphide. Either source may be a laser.