Abstract:
A nitride semiconductor light emitting device includes n-type and p-type nitride semiconductor layers, and an active layer disposed between the n-type and p-type nitride semiconductor layers and having a stack structure in which a plurality of quantum barrier layers and one or more quantum well layers are alternately stacked. A net polarization of the quantum barrier layer is smaller than or equal to a net polarization of the quantum well layer. A nitride semiconductor light emitting device can be provided, which can realize high efficiency even at high currents by minimizing the net polarization mismatch between the quantum barrier layer and the quantum well layer. Also, a high-efficiency nitride semiconductor light emitting device can be achieved by reducing the degree of energy-level bending of the quantum well layer.
Abstract:
An optical recording medium is provided, the optical recording medium including a plurality of zones configured to store data corresponding to an adaptive write pulse, the adaptive write pulse including a first pulse, a last pulse, and a multi-pulse train, the adaptive write pulse being different for each of the plurality of zones, the plurality of zones being reflected by a grouping table, the grouping table being configured to generate an adaptive write pulse waveform by varying a position of a rising edge of a first pulse of a mark to be written according to a length of the mark to be written and a leading space, the adaptive write pulse waveform being generated without regard for a trailing space of a present mark being written using the adaptive write pulse waveform, the adaptive write pulse being configured to correspond to the adaptive write pulse waveform, and store rising edge data of the first pulse of the adaptive write pulse waveform varying according to corresponding stored values of lengths of marks to be written. A width of the first pulse is varied by varying the position of the rising edge.
Abstract:
An apparatus configured to write input data on an optical recording medium using a write pulse waveform, the write pulse waveform including a first pulse, a last pulse and a multi-pulse train, is provided. The apparatus includes a discriminator configured to discriminate a magnitude of a present mark and a magnitude of a leading space from the input data, a write waveform controller configured to control the write pulse waveform to generate an adaptive write pulse waveform by varying a position of a rising edge of a first pulse of the present mark to be written according to the magnitude of the present mark and the magnitude of the leading space, and use a grouping table to control the write pulse waveform to generate the adaptive write pulse waveform, the grouping table being configured to store rising edge data of the first pulse of the write pulse waveform varying according to corresponding stored values of magnitudes of present marks and magnitudes of leading spaces, and a processor configured to process the input data on the optical recording medium using the adaptive write pulse waveform. The discriminator is further configured to apply the magnitude of the present mark and the magnitude of the leading space to the write waveform controller. The adaptive write pulse waveform is generated without regard for a trailing space of the present mark being written using the adaptive write pulse waveform. A width of the first pulse is varied by varying the position of the rising edge.
Abstract:
A method of fabricating a semiconductor memory device includes forming a hard mask pattern using a damascene method on a lower mold layer stacked on a substrate and etching the lower mold layer using the hard mask pattern as an etch mask to define a protrusion under the hard mask pattern. A support pattern is formed on a top surface of the etched lower mold layer, the top surface of the etched lower mold layer being located at a lower level than a top surface of the protrusion. A lower electrode supported by the support pattern is formed.
Abstract:
A nitride semiconductor light emitting device includes n-type and p-type nitride semiconductor layers; an active layer disposed between the n-type and p-type nitride semiconductor layers and having a structure in which a plurality of quantum barrier layers and one or more quantum well layers are alternately stacked; and an electron blocking layer disposed between the active layer and the p-type nitride semiconductor layer. The electron blocking layer has a superlattice structure in which two or more layers having different compositions are alternately stacked. An absolute value of a net polarization mismatch between a material, the material having a composition corresponding to an average composition of the superlattice structure, and a quantum barrier layer adjacent to the electron blocking layer among the plurality of quantum barrier layers is less than ⅔ of an absolute value of a net polarization mismatch between AlxG1-xN(0
Abstract translation:氮化物半导体发光器件包括n型和p型氮化物半导体层; 设置在n型和p型氮化物半导体层之间的有源层,并且具有多个量子势垒层和一个或多个量子阱层交替堆叠的结构; 以及设置在有源层和p型氮化物半导体层之间的电子阻挡层。 电子阻挡层具有超晶格结构,其中具有不同组成的两层或更多层交替堆叠。 在多个量子势垒层中,材料,具有对应于超晶格结构的平均组成的组成的材料和与电子阻挡层相邻的量子势垒层的材料之间的净偏振失配的绝对值小于 具有等于材料的带隙能量和不同于其的组成的Al x G 1-x N(0
Abstract:
Exemplary embodiments of the present invention disclose a light emitting diode (LED) and a method of fabricating the same. The LED includes a substrate, a semiconductor stack arranged on the substrate, the semiconductor stack including an upper semiconductor layer having a first conductivity type, an active layer, and a lower semiconductor layer having a second conductivity type, isolation trenches separating the semiconductor stack into a plurality of regions, connectors disposed between the substrate and the semiconductor stack, the connectors electrically connecting the plurality of regions to one another, and a distributed Bragg reflector (DBR) having a multi-layered structure, the DBR disposed between the semiconductor stack and the connectors. The connectors are electrically connected to the semiconductor stack through the DBR, and portions of the DBR are disposed between the isolation trenches and the connectors.
Abstract:
The present invention provides a method of fabricating a light emitting diode chip having an active layer between an N type semiconductor layer and a P type semiconductor layer. The method comprises the steps of preparing a substrate; laminating the semiconductor layers on the substrate, the semiconductor layers having the active layer between the N type semiconductor layer and the P type semiconductor layer; and forming grooves on the semiconductor layers laminated on the substrate until the substrate is exposed, whereby inclined sidewalls are formed by the grooves in the semiconductor layers divided into a plurality of chips. According to embodiments of the present invention, a sidewall of a semiconductor layer formed on a substrate of a light emitting diode chip is inclined with respect to the substrate, whereby its directional angle is widened as compared with a light emitting diode chip without such inclination. As the directional angle of the light emitting diode chip is wider, when a white light emitting device is fabricated using the light emitting diode chip and a phosphor, light uniformity can be adjusted even though the phosphor is not concentrated at the center of the device. Thus, the overall light emitting efficiency can be enhanced by reducing a light blocking phenomenon caused by the increased amount of the phosphor distributed at the center portion.