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.

A Vertical Cavity Surface Emitting Laser (VCSEL) includes a layer stack of semiconductor layers having a first layer sub-stack forming a mesa, and a second layer sub-stack adjacent to the mesa in a stacking direction. Layers of the second layer sub-stack extend beyond layers of the first sub-stack in a direction perpendicular to the stacking direction. The semiconductor layers of the layer stack form an optical resonator having a first mirror, a second mirror, an active region between the first and second mirrors for laser light generation, and an oxide aperture layer forming a current aperture. The oxide aperture layer is made from Al.sub.1-xGa.sub.xAs with 0≤x≤0.05. The oxide aperture layer is a last layer of the mesa and immediately adjacent to a first layer of the second layer sub-stack. A first layer of the second layer sub-stack is a contact layer.

A light-emitting device according to an embodiment of the present disclosure includes a laminate. The laminate includes an active layer, and a first semiconductor layer and a second semiconductor layer sandwiching the active layer. This light-emitting device further includes a current constriction layer having an opening and a vertical resonator including a first reflecting mirror having a concave-curved shape on the first semiconductor layer side and a second reflecting mirror on the second semiconductor side. The first reflecting mirror and the second reflecting mirror sandwich the laminate and the opening. This light-emitting device further includes an optically transparent substrate between the first reflecting mirror and the laminate. The optically transparent substrate has a first convex portion having a convex-curved shape and one or more second convex portions on a surface on the side opposite to the laminate. The first convex portion is in contact with the first reflecting mirror. The one or more second convex portions are provided around the first convex portion. The one or more second convex portions each have a height greater than or equal to a height of the first convex portion, and an end on the first reflecting mirror side has a convex-curved shape.

In some implementations, a surface emitting laser may have an emitter design with a short oxidation length and/or a large number of trenches. For example, the surface emitting laser may comprise a metallization layer comprising multiple extended portions extending outwards from a circumference of an inner ring portion, and multiple tabs extending laterally from the multiple extended portions in a partial ring shape. The surface emitting laser may further comprise multiple via openings connecting the metallization layer to a plating metal, where each via opening is positioned over a corresponding tab, of the multiple tabs. The surface emitting laser may comprise multiple oxidation trenches that are each formed in an angular gap between a pair of extended portions, of the multiple extended portions, such that the multiple tabs and the multiple via openings are exclusively outside outer radii of the multiple oxidation trenches.

A corrected mesa structure for a VCSEL device is particularly configured to compensate for variations in the shape of the created oxide aperture that result from anisotropic oxidation. In particular, a corrected mesa shape is derived by determining the shape of an as-created aperture formed by oxidizing a circular mesa structure, and then ascertaining the compensation required to convert the as-created shape into a desired (“target”) shaped aperture opening. The compensation value is then used to modify the shape of the mesa itself such that a following anisotropic oxidation yields a target-shaped oxide aperture.

A vertical-cavity surface-emitting laser (VCSEL) is provided. The VCSEL includes a mesa structure disposed on a substrate. The mesa structure includes a first reflector, a second reflector, and an active cavity material structure disposed between the first and second reflectors. The second reflector has an opening extending from a second surface of the second reflector into the second reflector by a predetermined depth. Etching into the second reflector to the predetermined depth reduces the photon lifetime and the threshold gain of the VCSEL, while increasing the modulation bandwidth and maintaining the high reflectivity of the second reflector. Thus, etching the second reflector to the predetermined depth provides an improvement in overshoot control, broader modulation bandwidth, and faster pulsing of the VCSEL such that the VCSEL may provide a high speed, high bandwidth signal with controlled overshoot.

Disclosed is an electrically pumped vertical cavity laser structure operating in the mid-infrared region, which has demonstrated room-temperature continuous wave operation. This structure uses an interband cascade gain region, two distributed mirrors, and a low-loss refractive index waveguide. A preferred embodiment includes at least one wafer bonded GaAs-based mirror.

An array of surface-emitting lasers is provided. The array outputs high brightness in a unipolar way. The array comprises a stress-adjustment unit and a plurality of epitaxial device units. The stress-adjustment unit is used to adjust stress. The stress from a substrate is used to select a laser mode for an aperture unit. The selection of the laser mode is enhanced for the aperture unit without sacrificing driving current. Low current operation is achieved in a single mode for effectively reducing volume and further minimizing the size of the whole array to achieve high-quality laser output. An object can be scanned by the outputted laser to obtain a clear image with a high resolution. Hence, the present invention is applicable for face recognition with high recognition and high security.

A vertical cavity surface-emitting laser epitaxial structure having a current spreading layer is disclosed. The vertical cavity surface-emitting laser epitaxial structure includes a substrate, a first epitaxial region on the substrate, an active region on the first epitaxial region, and a current spreading layer disposed in the first epitaxial region. The current spreading layer includes an N-type dopant, and the N-type dopant is selected from a group consisting of Si, Se, and the combination thereof. The current spreading layer does not directly contact the active region.

A vertical cavity surface emitting laser (VCSEL) may include an epitaxial structure that includes a first active layer, a second active layer, and a tunnel junction therebetween. The VCSEL may include a set of contacts that are electrically connected to the epitaxial structure. The set of contacts may include three or more contacts, and the set of contacts may be electrically separated from each other on the VCSEL. At least one contact, of the set of contacts, may be electrically connected to the epitaxial structure at a depth between the first active layer and the second active layer.