| 摘要 |
1496599 Electroluminescence NORTHERN TELECOM Ltd 13 Aug 1975 [17 Sept 1974] 33750/75 Heading C4S [Also in Division H1] In a stripe electrode semi-conductor heterostructure laser, the width of the ribbon output beam is controlled by applying a potential to one or more auxiliary electrodes. With a suitably limited current between the main electrodes of the semiconductor, such control enables the laser to switch from a non-lasing to a lasing condition as the width of the output beam is reduced, and vice versa. The laser consists basically of confining layers 21 and 23 of AlGaAs, Fig. 3, a GaAs laser active layer 22, and a GaAs capping layer 24, the layers being epitaxially grown on a substrate layer 20. The layers 20, 21 and layers 22, 23, 24 are of opposite conductivity type. Dopants may be Al, Te, Ge or Sn. In Fig. 3 a zinc diffusion zone 27 is provided, together with main and auxiliary electrodes 28a, 28b which are formed by evaporating Au/Ge, followed by Au, in windows 26 in an oxide layer 25. A main electrode 29 is similarly formed on the substrate. A modified semi-conductor construction providing a Schottky barrier type device is shown in Fig. 4, the constructional process involving the selective slight etching of regions of layer 24 to remove skin diffusion, followed by the deposition of layer 32 which is then stripe etched to provide main and auxiliary electrodes 32a, 32b. A metal insulator semi-conductor is also described, Fig. 5, in which layer 24 is selectively diffused to form region 35, followed by the selective deposition of an oxide layer 36 in areas 37. Main and auxiliary contacts 38 and 39 are then deposited on the regions 35 and 37, respectively. The laser may function as a modulator or as on-off switch with a suitability for a pulse modulation system. |
