At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Uri Levy

Eugene I Gordon

Room temperature laser action is achieved in a cathode ray tube (CRT) in which the target includes a plurality of semiconductor layers: a thin, wide bandgap buffer layer; a thicker, narrow bandgap active layer; and a much thicker wide bandgap cavity-length-adjusting layer. The light beam direction is essentially parallel to the e-beam direction and hence is scannable.

Method of making a semiconductor laser CRT

In a CRT display device the target comprises a multilayered semiconductor including a p-n junction and at least one current-blocking layer. The e-beam is locally absorbed in the current-blocking layer so as to open a narrow zone which allows charge to flow through the forward biased p-n junction. The injection current produces a local spot of light which radiates from the opposite side of the device and whose position is varied by scanning the e-beam. In one embodiment the current-blocking layer is a semi-insulating semiconductor layer, and in another embodiment the current-blocking layer comprises the base of a normally cut-off transistor.

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Berkeley Heights, NJ, United States of America

Uri Levy