Abstract: An illumination device includes a first light source that emits first light having a first peak wavelength which is highest in intensity in a wavelength range from near-ultraviolet to green in an emission spectrum; a second light source that emits second light having a second peak wavelength which is highest in intensity in a wavelength range from near-ultraviolet to green in an emission spectrum, the second light illuminating a position identical to a position illuminated by the first light; and a detection device that detects whether an object is present at a given position, wherein the second peak wavelength is shorter than the first peak wavelength, and a luminous flux of the first light is decreased and a luminous flux of the second light is increased when the detection device detects that the object is present at the predetermined position.

Abstract: An illumination device includes a first light source that emits first light having a first peak wavelength which is highest in intensity in a wavelength range from near-ultraviolet to green in an emission spectrum; a second light source that emits second light having a second peak wavelength which is highest in intensity in a wavelength range from near-ultraviolet to green in an emission spectrum, the second light illuminating a position identical to a position illuminated by the first light; and a detection device that detects whether an object is present at a given position, wherein the second peak wavelength is shorter than the first peak wavelength, and a luminous flux of the first light is decreased and a luminous flux of the second light is increased when the detection device detects that the object is present at the predetermined position.

Abstract: In a light emitting element, a semiconductor layer including a light emitting layer is stacked on a GaN substrate 11, and a surface of the GaN substrate 11 opposite to the stacked semiconductor layer serves as a main light emission surface S. At the main light emission surface S, quadrangular pyramid shaped protrusions 11a which are continuously arranged and whose standing direction F2 is displaced from a stacking direction of the semiconductor layer are formed. In each protrusion 11a, fine asperities are, by etching, preferably formed at least at an inclined surface having a small inclination angle. Moreover, each protrusion 11a may be in a truncated shape, but is preferably formed in a pointed shape.

Abstract: A method for manufacturing p-type nitride semiconductor comprising a semiconductor layer forming process where a low resistivity p-type nitride semiconductor layer is formed on a substrate by introducing the sources of p-type dopant, nitrogen and Group III sources on a substrate held at a temperature of 600° C. or higher and a cooling process for cooling the substrate which is bearing the p-type nitride semiconductor layer. The manufacturing method features in that the hole carrier concentration of the p-type nitride semiconductor layer decreases during the cooling process. A superior quality p-type nitride semiconductor is made available, without needing any annealing treatment after growth, by properly specifying the concentration of atmosphere gas and the cooling time.

Abstract: A method for manufacturing p-type nitride semiconductor comprising a semiconductor layer forming process where a low resistivity p-type nitride semiconductor layer is formed on a substrate by introducing the sources of p-type dopant, nitrogen and Group III sources on a substrate held at a temperature of 600° C. or higher and a cooling process for cooling the substrate which is bearing the p-type nitride semiconductor layer. The manufacturing method features in that the hole carrier concentration of the p-type nitride semiconductor layer decreases during the cooling process. A superior quality p-type nitride semiconductor is made available, without needing any annealing treatment after growth, by properly specifying the concentration of atmosphere gas and the cooling time.

Abstract: A method and apparatus for forming a semiconductor thin layer on a substrate surface employs a gas outlet for supplying gas to the substrate, a rotatable holder for holding the substrate thereon such that a surface of the substrate is exposed to the gas while the substrate orbits with rotation of the holder, and a heater generates and supplies heat energy to the substrate. A cover wall extends over the surface of the substrate which is exposed to the gas. A distance between the exposed surface of the substrate and the cover wall in a direction parallel to a rotational axis of the rotatable holder decreases radially outward over the substrate orbiting with rotation of the holder about a rotational axis of the holder.

Abstract: In the present invention, by organometallic vapor deposition, a buffer layer containing indium is grown on a substrate and an n-type gallium nitride compound-based semiconductor thin film containing indium is grown on the buffer layer. Thus, the occurrence of distortion and crystal defects in the vicinity of the boundary surface between the buffer layer and the n-type gallium nitride compound-based semiconductor thin film is reduced, so that the gallium nitride compound-based semiconductor thin film having an excellent crystallinity can be obtained.As a gallium nitride compound-based semiconductor light emitting device using gallium nitride compound-based semiconductor thin films which has excellent light-emitting properties, there can be obtained a gallium nitride compound-based semiconductor light emitting device comprising a substrate, a buffer layer of Al.sub.1-x In.sub.x N (0<.times.