Solid state light emitting diode wherein output is controlled by controlling election population of an intermediate level with an auxiliary light source

Claim 2

A controllable injection recombination radiation source comprising a semiconductive body of a material having a forbidden gap between its valence and conduction bands and within the forbidden gap a deep-lying impurity level defining between one of the conduction band and the valence band, and the impurity level a radiative transition, a pair of electrodes coupled to the semiconductive body, means for applying voltages to the electrodes to cause the injection of charge carriers and the establishment of free electrons in the conduction band, said electrons tending to radiatively recombine via the said impurity level by means of a radiative transition to the impurity level, and an auxiliary voltage-responsive radiation source optically coupled to the semiconductive body for controllably irradiating same with radiant energy capable of bringing electrons from the valence band to the said impurity level to increase the electron population thereof, said electron population increase of the impurity level reducing the probability of the said radiative transition and thereby reducing in a controlled manner the output radiation from said semiconductive body.

Claim 3

A controllable injection recombination radiation source as set forth in claim 1 wherein the radiative transition is from the conduction band to the impurity level, and the energy content of the radiation from the auxiliary source is large enough to bring electrons from the valence band to the impurity level, but is too small to cause the transition from the impurity level to the conduction band.

Claim 4

A controllable injection recombination radiation source as set forth in claim 2 wherein the material of said semiconductive body is constituted of gallium phosphide doped with zinc and oxygen and contains a PN-junction.

Claim 5

A controllable injection recombination radiation source comprising a semiconductive body of a material having a forbidden gap between its valence and conduction bands providing a radiative transition and within the forbidden gap a deep-lying impurity level defining between both the conduction band and the valence band and the impurity level radiationless transitions, a pair of electrodes coupled to the semiconductive body, means for applying voltages to the electrodes to cause the injection of charge carriers and the establishment of free electrons in the conduction band, said electrons tending to radiatively recombine via a band-to-band transition or via an impurity level or to effect a radiationless recombination via the deep-lying level, and an auxiliary voltage-responsive radiation source optically coupled to the semiconductive body for controllably irradiating same with energy capable of bringing electrons from the valence band to the said deep-lying impurity level to increase the electron population thereof or capable of bringing electrons from the deep-lying impurity level to the conduction band to decrease the population of the deep-lying level, said electron population variation of the deep-lying impurity level reducing the probability of the said radiationless transition and thereby increasing in a controlled manner the output radiation from said semiconductive body.

Claim 6

A controllable injection recombination radiation source comprising a semiconductive body of a material having a forbidden gap between its valence and conduction bands providing a radiative transition and within the forbidden gap a deep-lying impurity level defining between both the conduction band and the valence band and the impurity level radiationless transitions, a pair of electrodes coupled to the semiconductive body, means for applying voltages to the electrodes to cause the injection of charge carriers and the establishment of free electrons in the conduction band, said electrons tending to radiatively recombine via a band-to-band transition or via an impurity level or to effect a radiationless recombination via the deep-lying level, and an auxiliary voltage-responsive radiation source optically coupled to the semiconductive body for controllably irradiating same with energy capable of bringing electrons from the valence band to the said deep-lying impurity level to increase the electron population thereof or capable of bringing electrons from the deep-lying impurity level to the conduction band to decrease the population of the deep-lying level, said electron population variation of the deep-lying impurity level reducing the probability of the said radiationless transition and thereby increasing in a controlled manner the output radiation from said semiconductive body.

Claim 7

A controllable recombination radiation source as set forth in claim 4 wherein the semiconductor body is constituted of gallium phosphide doped with zinc and oxygen and containing a PN-junction.