US 4,881,235 A · Semiconductor laser having a multiple quantum well structure doped with impurities

Abstract

In a well-known semiconductor laser, a multiple quantum well type active layer consisting of barrier layers and active layers or well layers, each of which has a thickness less than the de Broglie wavelength of electrons, is doped with an impurity, and the impurity density is made higher in the barrier layer than in the well layer. Further, in a case where the multiple quantum well active layer is held between p-type and n-type cladding layers, the well layer is undoped, the part of the barrier layer lying in contact with the well layer is undoped, and the other part of the barrier layer close to the p-type cladding layer is put into the n-conductivity type while that of the barrier layer close to the n-type cladding layer is put into the n-conductivity type. Desirably, the impurity density should range from about 1.times.10.sup.18 to about 1.times.10.sup.19 cm.sup.- 3.

Claims40

Dependent claims

A semiconductor laser comprising:

a semiconductor substrate;
a plurality of semiconductor layers formed on the substrate, the plurality of semiconductor layers including a cladding layer, at least one active layer and at least one barrier layer, the at least one active layer and at least one barrier layer being stacked alternately so as to form a multiple quantum well structure and together forming an active region, and a resonant cavity including said active region, wherein the at least one active layer respectively has a thickness that is smaller than a wave packet of free electrons within a crystal, and wherein the active region has a light emitting portion in which there is a part doped with impurities, the impurity concentration thereof being larger than 10.sup.18 cm.sup.-3 ;
and
a pair of electrodes for injecting carriers into the light emitting portion, to emit light.

1 more element

A semiconductor laser comprising:

a semiconductor substrate;
a plurality of semiconductor layers formed on the substrate, the plurality of semiconductor layers including a multiple quantum well active region formed of at least one active layer and at least one barrier layer stacked alternately, and also including first conductivity type and second conductivity type cladding layers respectively sandwiching the multiple quantum well active region, the first and second conductivity types being opposite conductivity types to each other, the at least one active layer each having a thickness less than the de Broglie wavelength of electrons, the at least one barrier layer having a bandgap greater than that of the at least one active layer, the cladding layers having a bandgap larger than that of the at least one active layer, wherein the multiple quantum well active region has a light emitting portion in which there is a part doped with impurities, the impurity concentration thereof being greater than 10.sup.18 cm.sup.-3, and wherein the laser includes a resonant cavity including said multiple quantum well active region;
and
a pair of electrodes for injecting carriers into the light emitting portion, to emit light.

1 more element

Dependencies are inferred from the claim text.

Semiconductor laser having a multiple quantum well structure doped with impurities

Life of this patent

Semiconductor laser having a multiple quantum well structure doped with impurities

Life of this patent

Abstract

Claims40