A team led by Chen Hong of the Chinese Academy of Sciences produced a white LED with indium-rich quantum dots, which is more advantageous than white light emitted by blue-excited yellow phosphors. He said, "We have provided a new way to get rid of the limitations of lower phosphorescence." It is reported that compared with conventionally designed LEDs, phosphorus-free devices ensure longer device life and higher output efficiency.
   An LED chip having a size of 300 × 300 μm was fabricated by low-pressure MOCVD growth on a sapphire substrate. The method is such that a 3 μm thick buffer layer, 220 nm thick InGaN, a four-layer active region including a 3 nm InGaN quantum well, a 14 nm GaN barrier layer, and a p-type region are sequentially grown.
Transmission electron microscopy showed spinodial decomposition of InGaN in the quantum well. This phase difference caused by the InGaN underlayer produced an indium-rich quantum well with a diameter of 3?C4nm and a dislocation density of 1012 cm?C2.
   The LED's drive current is less than 5 mA, and the yellow light from the quantum dots is the main part of the device's output, but the blue light dominates at higher currents. Moreover, the luminous density of blue-yellow light composed in a certain ratio is almost a constant between 20-60 mA.
   A stable white light is output in this current range, and the chip prepared by this technology is suitable for LED illumination. Chen Hong said that in fact, when the current changes, it will be affected by many problems when the fluorescent light turns into white light. The device can overcome some unnecessary color changes.
   If a quantum dot LED wants to replace a bulb for general illumination, then the ratio of blue to yellow density should be stable at higher drive currents. This is bound to become a major obstacle. However, at current chip currents of 60 mA, its current density is approximately the same as that of a 1 x 1 mm power chip at 700 mA.
   The bottom side of the phosphorus-free device is a singularity with a luminous efficiency of less than 10 lm/W, and researchers are planning to develop new techniques to increase quantum efficiency. Chen Hong explained, "We also need to study how to control the ratio of blue and yellow light density, and also to understand whether yellow light can drift to longer wavelengths." If you do both, then increasing the color rendering index of the device is just around the corner. (Source: Journal reference)
   An LED chip having a size of 300 × 300 μm was fabricated by low-pressure MOCVD growth on a sapphire substrate. The method is such that a 3 μm thick buffer layer, 220 nm thick InGaN, a four-layer active region including a 3 nm InGaN quantum well, a 14 nm GaN barrier layer, and a p-type region are sequentially grown.
Transmission electron microscopy showed spinodial decomposition of InGaN in the quantum well. This phase difference caused by the InGaN underlayer produced an indium-rich quantum well with a diameter of 3?C4nm and a dislocation density of 1012 cm?C2.
   The LED's drive current is less than 5 mA, and the yellow light from the quantum dots is the main part of the device's output, but the blue light dominates at higher currents. Moreover, the luminous density of blue-yellow light composed in a certain ratio is almost a constant between 20-60 mA.
   A stable white light is output in this current range, and the chip prepared by this technology is suitable for LED illumination. Chen Hong said that in fact, when the current changes, it will be affected by many problems when the fluorescent light turns into white light. The device can overcome some unnecessary color changes.
   If a quantum dot LED wants to replace a bulb for general illumination, then the ratio of blue to yellow density should be stable at higher drive currents. This is bound to become a major obstacle. However, at current chip currents of 60 mA, its current density is approximately the same as that of a 1 x 1 mm power chip at 700 mA.
   The bottom side of the phosphorus-free device is a singularity with a luminous efficiency of less than 10 lm/W, and researchers are planning to develop new techniques to increase quantum efficiency. Chen Hong explained, "We also need to study how to control the ratio of blue and yellow light density, and also to understand whether yellow light can drift to longer wavelengths." If you do both, then increasing the color rendering index of the device is just around the corner. (Source: Journal reference)
Fast thyristors (Inverter Thyristor)are used for higher frequency rectification. Inverter and inverter circuit appliances.
Rectifiers have many uses, but are often found serving as components of DC power supplies and high-voltage direct current power transmission systems. Rectification may serve in roles other than to generate direct current for use as a source of power. As noted, detectors of radio signals serve as rectifiers. In gas heating systems flame rectification is used to detect presence of a flame.
Inverter Thyristor,Power Inverter Thyristor,Frequency Inverter Thyristor,Electronic Component Inverter Thyristor,Bi-directional Controlled Thyristors (BCT)
YANGZHOU POSITIONING TECH CO., LTD. , https://www.cnfudatech.com