Abstract: Disclosed herein are a material layer stack, a light emitting element, a light emitting package, and a method of fabricating a light emitting element. The material layer stack includes: a substrate having a first lattice constant; and a semiconductor layer grown on the substrate, the semiconductor layer having a second lattice constant that is different from the first lattice constant. Using the material layer stack, a light emitting element having a low leakage current, a low operation voltage, and an excellent luminous efficiency can be obtained.

Abstract: A lighting system includes a lighting unit comprising at least one lighting device, a sensing unit configured to measure at least one of atmospheric temperature and humidity, a controlling unit configured to compare the at least one of the temperature and the humidity measured by the sensor unit with set values and determine a color temperature of the lighting unit as a result of the comparison, and a driving unit configured to drive to the lighting unit to have the determined color temperature.

Abstract: Disclosed herein are a material layer stack, a light emitting element, a light emitting package, and a method of fabricating a light emitting element. The material layer stack includes: a substrate having a first lattice constant; and a semiconductor layer grown on the substrate, the semiconductor layer having a second lattice constant that is different from the first lattice constant. Using the material layer stack, a light emitting element having a low leakage current, a low operation voltage, and an excellent luminous efficiency can be obtained.

Abstract: A method of manufacturing a semiconductor light-emitting device is provided. The method includes operations of forming a first conductive type semiconductor layer on a substrate; forming a V-pit in the first conductive type semiconductor layer; forming a defect decreasing structure in and over the V-pit; and forming a residual first conductive type semiconductor layer on the defect decreasing structure. By using the method, an excellent-quality semiconductor light-emitting device having a reduced crystal defect may be inexpensively manufactured.

Abstract: An apparatus for evaluating the quality of a crystal includes an optical device that measures a surface reflectance of a wafer in which a V-pit is formed; and a data processing unit that calculates a threading dislocation density by calculating a difference in surface reflectance of the wafer that is measured by the optical device.

Abstract: A lighting system includes a lighting unit comprising at least one lighting device, a sensing unit configured to measure at least one of atmospheric temperature and humidity, a controlling unit configured to compare the at least one of the temperature and the humidity measured by the sensor unit with set values and determine a color temperature of the lighting unit as a result of the comparison, and a driving unit configured to drive to the lighting unit to have the determined color temperature.

Abstract: A method for fabricating a nitride semiconductor thin film includes preparing a first nitride single crystal layer doped with an n-type impurity. A plurality of etch pits are formed in a surface of the first nitride single crystal layer by applying an etching gas thereto. A second nitride single crystal layer is grown on the first nitride single crystal layer having the etch pits formed therein.

Abstract: A semiconductor light emitting device may include: a first conductivity type semiconductor layer; an active layer disposed on the first conductivity type semiconductor layer; an electron-blocking layer disposed on the active layer; a second conductivity type semiconductor layer disposed on the electron-blocking layer; and a hole-diffusion layer disposed between the electron-blocking layer and the second conductivity type semiconductor layer. The hole-diffusion layer may include three layers having different energy band gaps and different resistance levels and at least one of the three layers may contain Al. A composition of the Al may be lower in the at least one layer than in the electron-blocking layer.

Abstract: A method of fabricating a nitride semiconductor light emitting device is provided. The method includes growing a first group-III-nitride semiconductor layer on a substrate, the first group-III-nitride semiconductor layer having a top surface formed as a group-III-rich surface exhibiting a group-III-polarity and a bottom surface formed as a N-rich surface exhibiting a N-polarity. The method further includes selectively etching a N-polarity region in the top surface of the first group III nitride semiconductor layer, forming a second group III nitride semiconductor layer on the first group III nitride semiconductor layer to fill the etched N-polarity region and forming a light emitting structure including first and second conductivity type nitride semiconductor layers and an active layer on the second group III nitride semiconductor layer.

Abstract: An apparatus for evaluating the quality of a crystal includes an optical device that measures a surface reflectance of a wafer in which a V-pit is formed; and a data processing unit that calculates a threading dislocation density by calculating a difference in surface reflectance of the wafer that is measured by the optical device.

Abstract: A method for fabricating a nitride semiconductor thin film includes preparing a first nitride single crystal layer doped with an n-type impurity. A plurality of etch pits are formed in a surface of the first nitride single crystal layer by applying an etching gas thereto. A second nitride single crystal layer is grown on the first nitride single crystal layer having the etch pits formed therein.

Abstract: A method of fabricating a nitride semiconductor light emitting device is provided. The method includes growing a first group-III-nitride semiconductor layer on a substrate, the first group-III-nitride semiconductor layer having a top surface formed as a group-III-rich surface exhibiting a group-III-polarity and a bottom surface formed as a N-rich surface exhibiting a N-polarity. The method further includes selectively etching a N-polarity region in the top surface of the first group III nitride semiconductor layer, forming a second group III nitride semiconductor layer on the first group III nitride semiconductor layer to fill the etched N-polarity region and forming a light emitting structure including first and second conductivity type nitride semiconductor layers and an active layer on the second group III nitride semiconductor layer.