A light-emitting element includes: a first light-emitting portion includes, in order upward from a lower side, a first n-side layer, a first active layer, and a first p-side layer disposed, each made of a nitride semiconductor; an intermediate layer disposed over the first light-emitting portion and made of a nitride semiconductor including an n-type impurity; and a second light-emitting portion disposed over the intermediate layer and comprising, in order upward from a lower side, a second n-side layer, a second active layer, and a second p-side layer, each made of a nitride semiconductor. An n-type impurity concentration in the intermediate layer is greater than an n-type impurity concentration in the first n-side layer. The first p-side layer includes: a first layer including aluminum and gallium, and a second layer disposed above the first layer, including aluminum and gallium.

A light emitting diode includes a n-doped region, a p-doped region, and a light emitting region located between the n-doped region and a p-doped region. The n-doped region includes a first GaN layer, at least one n-doped second GaN layer located over the first GaN layer, an AlGaN dislocation blocking layer located over the at least one n-doped second GaN layer, and a n-doped third GaN layer located over the AlGaN dislocation blocking film.

A light emitting device (LED) includes an n-doped semiconductor material layer, an active region including an optically active compound semiconductor layer stack configured to emit light located on the n-doped semiconductor material layer, a p-doped semiconductor material layer located on the active region, an anode contact contacting the p-doped semiconductor material layer, a reflector overlying and electrically connected to the anode contact, and a device-side bonding pad layer located on the reflector. The p-doped semiconductor material layer includes an electrically active region that is at least partially covered by the anode contact and an inactive region that an electrical conductivity less than 30% of the electrically active region.

A nitride semiconductor light-emitting element at least includes an underlayer, an n-type contact layer, a light-emitting layer, and a p-type nitride semiconductor layer successively disposed on a substrate. The film thickness ratio R, the ratio of the thickness of the n-type contact layer to the thickness of the underlayer, is 0.8 or less. The number density of V-pits in the surface of the light-emitting layer located on the p-type nitride semiconductor layer side is 1.5×10.sup.8/cm.sup.2 or less. This can provide a nitride semiconductor light-emitting element that can realize improvements in the light emission efficiency at the actual operating temperature and the temperature characteristic and an improvement in the ESD resistance without causing conflict.

A semiconductor layer sequence includes a first nitridic compound semiconductor layer, a second nitridic compound semiconductor layer, and an intermediate layer arranged between the first and second nitridic compound semiconductor layers. Beginning with the first nitridic compound semiconductor layer, the intermediate layer and the second nitridic compound semiconductor layer are arranged one after the other in a direction of growth of the semiconductor layer sequence and are adjacent to each other in direct succession. The intermediate layer has a lattice constant different from the lattice constant of the first nitridic compound semiconductor layer at least at some points. The second nitridic compound semiconductor layer is lattice-adapted to the intermediate layer at least at some points.

A nitride semiconductor element includes a sapphire substrate including: a main surface extending in a c-plane of the sapphire substrate, and a plurality of projections disposed at the main surface, the plurality of projections including at least one projection having an elongated shape in a plan view; and a nitride semiconductor layer disposed on the main surface of the sapphire substrate. The at least one projection has an outer edge extending in a longitudinal direction of the elongated shape, the outer edge extending in a direction oriented at an angle in a range of −10° to +10° with respect to an a-plane of the sapphire substrate in the plan view.

A UV light emitting device is disclosed. The UV light emitting device includes: a substrate; an n-type semiconductor layer disposed on the substrate; an active layer disposed on the n-type semiconductor layer; a hole injection layer disposed on the active layer and comprising Al; an Al-delta layer disposed on the hole injection layer and comprising Al; and a first p-type contact layer disposed on the Al-delta layer and having a higher doping concentration of p-type dopants than the hole injection layer, wherein the first p-type contact layer has a lower Al content than the hole injection layer, a band-gap of the first p-type contact layer is lower than or equal to energy of light emitted from the active layer, and the Al-delta layer has a higher Al content than the hole injection layer and allows holes to enter the active layer by tunneling therethrough.

An epitaxial wafer comprises an epitaxial layer disposed on a substrate. The epitaxial layer comprises first to third semiconductor layers. The third semiconductor layer has a thickness that is thicker than that of the first semiconductor layer. A second doping density of the second semiconductor layer is between a first doping density of the first semiconductor layer and a third doping density of the third semiconductor layer.

A nitride semiconductor light-emitting element includes at least an n-type nitride semiconductor layer, a light-emitting layer, and a p-type nitride semiconductor layer. A multilayer body is provided between the n-type nitride semiconductor layer and the light-emitting layer, having at least one stack of first and second semiconductor layers. The second semiconductor layer has a greater band-gap energy than the first semiconductor layer. The first and second semiconductor layers each have a thickness of more than 10 nm and 30 nm or less. In applications in which luminous efficiency at room temperature is a high priority, the first semiconductor layer has a thickness of more than 10 nm and 30 nm or less, the second semiconductor layer has a thickness of more than 10 nm and 40 nm or less, and the light-emitting layer has V-shaped recesses in cross-sectional view.

The present invention relates to the radiant artificial lunar light system that contains effective elements for the growth of plants. To explain more specifically, the radiant artificial lunar light system emits lights containing the main mineral materials distributed on the oceanic region of the moon, such as Si, Ti, Fe, Mg, Ca, Na, K, P, Mn, Cr, etc. each doped with a doner by the plural PN bond-type semiconductors' photon device modules; and plural PN bond-type semiconductors' photon device modules; and plural PN bond-type semiconductors' LED modules emitting lights of certain intensity, in order to form the radiant artificial lunar light system. If this system is turned into operation, using the microcomputer equipped with a means to control, controlling the wavelengths and luminous intensity, the radiant artificial lunar lights similar in nature (spectra) to the lights emitted from the oceanic and highland regions of the moon are made available so that the artificial lunar lights can supply the plants with the mineral elements for the plants to grow more effectively.