Laser device characterized in that it comprises, as gain medium, a film of colloidal nanocrystals of semiconductor material, wherein said nanocrystals are two-dimensional nanocrystals suitable for forming quantum wells for confinement of the charge carriers in the nanocrystals and having a biexciton gain mechanism.

Laser device characterized in that it comprises, as gain medium, a film of colloidal nanocrystals of semiconductor material, wherein said nanocrystals are two-dimensional nanocrystals suitable for forming quantum wells for confinement of the charge carriers in the nanocrystals and having a biexciton gain mechanism.

The present invention relates to a method for obtaining an n-type doped metal chalcogenide quantum dot solid-state element with optical gain for low-threshold, band-edge amplified spontaneous emission (ASE), comprising: forming a metal chalcogenide quantum dot solid-state element, and carrying out an n-doping process on its metal chalcogenide quantum dots to at least partially bleach its band-edge absorption, which comprises: a partial substitution of chalcogen atoms by halogen atoms, in the metal chalcogenide quantum dots, and/or a partial aliovalent-cation substitution of bivalent metal cations by trivalent cations, in the metal chalcogenide quantum dots; and providing a substance on the metal chalcogenide quantum dots, to avoid oxygen p-doping. The present invention also relates to the obtained n-type doped metal chalcogenide quantum dot solid-state element, a method for obtaining a light emitter with that n-type doped metal chalcogenide quantum dot solid-state element, and the obtained light emitter.

The present invention relates to a method for obtaining an n-type doped metal chalcogenide quantum dot solid-state element with optical gain for low-threshold, band-edge amplified spontaneous emission (ASE), comprising: forming a metal chalcogenide quantum dot solid-state element, and carrying out an n-doping process on its metal chalcogenide quantum dots to at least partially bleach its band-edge absorption, which comprises: a partial substitution of chalcogen atoms by halogen atoms, in the metal chalcogenide quantum dots, and/or a partial aliovalent-cation substitution of bivalent metal cations by trivalent cations, in the metal chalcogenide quantum dots; and providing a substance on the metal chalcogenide quantum dots, to avoid oxygen p-doping. The present invention also relates to the obtained n-type doped metal chalcogenide quantum dot solid-state element, a method for obtaining a light emitter with that n-type doped metal chalcogenide quantum dot solid-state element, and the obtained light emitter.

In order to provide a THz-QCL element which takes advantage of the characteristics of a ZnO-based semiconductor material, a quantum cascade laser element has a semiconductor superlattice structure (a QCL structure), wherein the semiconductor superlattice structure has a plurality of unit structures that are stacked repeatedly. Each unit structures comprises three well layers having a composition of ZnO or ZnMgO, and barrier layers having a composition of ZnMgO or MgO that separates each well layer from each other and have a higher ratio of MgO than the left and right wells.

In order to provide a THz-QCL element which takes advantage of the characteristics of a ZnO-based semiconductor material, a quantum cascade laser element has a semiconductor superlattice structure (a QCL structure), wherein the semiconductor superlattice structure has a plurality of unit structures that are stacked repeatedly. Each unit structures comprises three well layers having a composition of ZnO or ZnMgO, and barrier layers having a composition of ZnMgO or MgO that separates each well layer from each other and have a higher ratio of MgO than the left and right wells.