Abstract: This structure comprises a heterostructure formed from first, second and third stacked semiconductor layer, the first and third layers being of N-GaAlAs having a forbidden band width at least equal to that of the materials forming the second layer constituting the active layer of the structure, said second layer being formed from a super-lattice having thin layers of P-GaAs and thin layers of P-GaAlAs in alternating form and oriented parallel to the first and third layers, a N region extending at least from one face to the other of the third layer defining with the latter the PN junction of the laser and means for supplying the laser and transistor with current.

Abstract: A phototransistor comprising a substrate (9), a collector layer (2), a base layer (3), and an emitter layer (4) is disclosed. The base layer (3) is of a first composite III-V semiconductor material with a first type of doping and the emitter layer (4) is of a second composite III-V semiconductor material. A diffusion well (6), of the first type of doping extends on a main part of the emitter layer (4) down to the base layer. The remaining part of the emitter layer (4) is of a second type of doping. The main part of the emitter layer (4) has an area at least 100 times larger than the area of the remaining part. A contact layer with the second type of doping is deposited on the remaining part of the emitter layer (4) with an emitter contact on the contact layer, and a base contact on an extremity of the diffusion well (6).