The present application provides an epitaxial wafer of a red light-emitting diode, and a preparation method therefor, by designing an n-type semiconductor layer as a gradient layer with the content of an aluminum element gradually increasing along a growth direction of the epitaxial wafer and the content of an indium element gradually decreasing along a stacking direction of the epitaxial wafer, and a constant layer with the content of an aluminum element and an indium element not changing along the growth direction of the epitaxial wafer, the potential barrier at the side close to a multi-quantum well layer gradually rises, preventing electrons and holes in the multi-well quantum layer for radiative recombination from moving to the outside of the MQW region, confining the holes and electrons to have a radiative recombination in the MQW and reducing non-radiative recombination, and also facilitating the flowing of electrons in the n-layer to the MQW region.

The present application provides an epitaxial wafer of a red light-emitting diode, and a preparation method therefor, by designing an n-type semiconductor layer as a gradient layer with the content of an aluminum element gradually increasing along a growth direction of the epitaxial wafer and the content of an indium element gradually decreasing along a stacking direction of the epitaxial wafer, and a constant layer with the content of an aluminum element and an indium element not changing along the growth direction of the epitaxial wafer, the potential barrier at the side close to a multi-quantum well layer gradually rises, preventing electrons and holes in the multi-well quantum layer for radiative recombination from moving to the outside of the MQW region, confining the holes and electrons to have a radiative recombination in the MQW and reducing non-radiative recombination, and also facilitating the flowing of electrons in the n-layer to the MQW region.

A light emitting device for a display including a first LED sub-unit, a second LED sub-unit disposed on the first LED sub-unit, a third LED sub-unit disposed on the second LED sub-unit, electrode pads disposed under the first LED sub-unit, each of the electrode pads being electrically connected to at least one of the first, second, and third LED sub-units, and lead electrodes electrically connected to the electrode pads and extending outwardly from the first LED sub-unit.

A light emitting device for a display including a first LED sub-unit, a second LED sub-unit disposed on the first LED sub-unit, a third LED sub-unit disposed on the second LED sub-unit, electrode pads disposed under the first LED sub-unit, each of the electrode pads being electrically connected to at least one of the first, second, and third LED sub-units, and lead electrodes electrically connected to the electrode pads and extending outwardly from the first LED sub-unit.

A semiconductor device is provided, which includes a first semiconductor structure, a second semiconductor structure and a light-emitting structure. The light-emitting structure is located between the first semiconductor structure and the second semiconductor structure. The light-emitting structure includes a multiple quantum well structure. The multiple quantum well structure contains aluminum and includes a plurality of semiconductor stacks. Each of the semiconductor stacks is stacked by a well layer and a barrier layer. In each semiconductor stack, the well layer has a thickness larger than a thickness of the barrier layer.

A semiconductor device is provided, which includes a first semiconductor structure, a second semiconductor structure and a light-emitting structure. The light-emitting structure is located between the first semiconductor structure and the second semiconductor structure. The light-emitting structure includes a multiple quantum well structure. The multiple quantum well structure contains aluminum and includes a plurality of semiconductor stacks. Each of the semiconductor stacks is stacked by a well layer and a barrier layer. In each semiconductor stack, the well layer has a thickness larger than a thickness of the barrier layer.

A wavelength converting structure is disclosed, the wavelength converting structure including an SWIR phosphor material having emission wavelengths in the range of 1000 to 1700 nm, the SWIR phosphor material including at least one of a perovskite type phosphor doped with Ni.sup.2+, a perovskite type phosphor doped with Ni.sup.2+ and Cr.sup.3+, and a garnet type phosphor doped with Ni.sup.2+ and Cr.sup.3+.

A wavelength converting structure is disclosed, the wavelength converting structure including an SWIR phosphor material having emission wavelengths in the range of 1000 to 1700 nm, the SWIR phosphor material including at least one of a perovskite type phosphor doped with Ni.sup.2+, a perovskite type phosphor doped with Ni.sup.2+ and Cr.sup.3+, and a garnet type phosphor doped with Ni.sup.2+ and Cr.sup.3+.

To improve light emission efficiency, in a light-emitting element including a first InAs layer that is undoped or doped with an n-type dopant; an active layer including one or more InAs.sub.ySb.sub.1-y layers (0<y<1); and a second InAs layer doped with a p-type dopant, an Al.sub.xIn.sub.1-xAs electron blocking layer (0.05≤x≤0.40) with a thickness of 5 nm to 40 nm is provided between the active layer and the second InAs layer.

To improve light emission efficiency, in a light-emitting element including a first InAs layer that is undoped or doped with an n-type dopant; an active layer including one or more InAs.sub.ySb.sub.1-y layers (0<y<1); and a second InAs layer doped with a p-type dopant, an Al.sub.xIn.sub.1-xAs electron blocking layer (0.05≤x≤0.40) with a thickness of 5 nm to 40 nm is provided between the active layer and the second InAs layer.