Abstract: A photoconductor for emitting and/or receiving electromagnetic waves is provided. The photoconductor comprises a material region comprising a first and a second section, wherein the second section provides a higher density of charge carrier trapping centers and/or recombination centers than the first section, and a confinement generating a sub-band structure of the charge carrier energy states in the material region. The first and the second section are arranged and configured in such a manner that a maximum of the carrier probability density of the sub-band ground state is located in one of these sections and a maximum of the carrier probability density of an excited sub-band state is located in the respective other section.

Abstract: The invention relates to a photoconductor for emitting and/or receiving electromagnetic waves, comprising a material region (1) comprising a first and a second section (A, C), wherein the second section (C) provides a higher density of charge carrier trapping centers and/or recombination centers than the first section (A), a confinement generating a sub-band structure of the charge carrier energy states in the material region (1), wherein the first and the second section (A,C) are arranged and configured in such a manner that a maximum of the carrier probability density (P1) of the sub-band ground state is located in one of these sections (A, C) and a maximum of the carrier probability density (P2) of an excited sub-band state is located in the respective other section.

Abstract: An embodiment of the invention relates to a cascade semiconductor light source comprising: a first block of cascades and a first contact region coupled to said first cascade, the first contact region being capable of injecting carriers into the first cascade of the first block; and a second block of cascades and a second contact region coupled to said second cascade, the second contact region being capable of injecting carriers into the second cascade; wherein the application of a first polarity voltage to said light source results in the cascades in the first block to be in an active mode and the cascades in the second block to be in an inactive mode; wherein the application of a second, opposite polarity voltage to said light source results in the cascades in the first block to be in an inactive mode and the cascades in the second block to be in an active mode; wherein the first block of cascades is adapted to emit light at a first wavelength in its active mode and to passively conduct electrical current in

Abstract: A quantum well structure according to the invention includes a quantum well layer (107) arranged between two barrier layers (109, 112). It is distinguished in that at least one of the barrier layers (109) includes nanostructures (110) which compensate or modulate a lateral homogeneity of the barrier layer (109), that exists without the nanostructures (110), that is to say a homogeneity in the directions extending perpendicularly to the stacking direction of the layers in the quantum well structure.

Abstract: A quantum cascade laser structure in accordance with the invention comprises a number of cascades (100), each of which comprises a number of alternately arranged quantum wells (110a to 110j) and barrier layers (105 to 105j). The material of at least one quantum well (110a to 110j) as well as the material of at least one barrier layer (105 to 105j) is under mechanical strain, with the respective strain being either a tensile strain or a compression strain. The quantum wells (110a to 110j) and barrier layers (105 to 105j) are engineered in the quantum cascade laser structure in accordance with the invention so that existing strains are largely compensated within a cascade (100). In the quantum cascade laser structure in accordance with the invention, each material of the quantum wells (110a to 110j) has only one constituent material and the material of at least one barrier layer (105d, 105e, 105f) has at least two constituent materials (111a, 111b, 112a, 112b, 113a, 113b).