A new epitaxial structure of AlGaInP-based light-emitting diode（LED） with a 0.5-μm GaP window layer was fabricated. In addition, indium tin oxide（ITO） and localized Cr deposition beneath the p-pad electrode were ...A new epitaxial structure of AlGaInP-based light-emitting diode（LED） with a 0.5-μm GaP window layer was fabricated. In addition, indium tin oxide（ITO） and localized Cr deposition beneath the p-pad electrode were used as the current spreading layer and the Schottky current blocking layer（CBL）, respectively. The results indicated that ITO and the Schottky CBL improve the total light extraction efficiency by relieving the current density crowding beneath the p-pad electrode. At the current of 20 mA, the light output power of the novel LED was 40% and 19% higher than those of the traditional LED and the new epitaxial LED without CBL. It was also found that the novel LED with ITO and CBL shows better thermal characteristics.展开更多
The light output power of an InGaN/GaN light-emitting diode is improved by using a SiO2/TiO2 distributed Bragg reflector （DBR） and an A1 mirror as a hybrid reflective current blocking layer （CBL）. Such a hybrid re...The light output power of an InGaN/GaN light-emitting diode is improved by using a SiO2/TiO2 distributed Bragg reflector （DBR） and an A1 mirror as a hybrid reflective current blocking layer （CBL）. Such a hybrid reflective CBL not only plays the role of the CBL by enhancing current spreading but also plays the role of a reflector by preventing photons near the p electrode pad from being absorbed by a metal electrode. At a wavelength of 455 nm, a 1.5-pair of SiO2/TiO2 DBR and an A1 mirror （i.e. 1.5-pair DBR＋A1） deposited on a p-GaN layer showed a normal-incidence reflectivity as high as 97.8%. With 20 mA current injection, it was found that the output power was 25.26, 24.45, 23.58 and 22.45 mW for the LED with a 1.5-pair DBR＋AI CBL, a 3-pair DBR CBL, SiO2 CBL and without a CBL, respectively.展开更多
A GaN vertical light emitting diode（LED）with a current block layer（CBL）was investigated.Vertical LEDs without a CBL,with a non-ohmic contact CBL and with a silicon dioxide CBL were fabricated.Optical and electrica...A GaN vertical light emitting diode（LED）with a current block layer（CBL）was investigated.Vertical LEDs without a CBL,with a non-ohmic contact CBL and with a silicon dioxide CBL were fabricated.Optical and electrical tests were carried out.The results show that the light output power of vertical LEDs with a non-ohmic contact CBL and with a silicon dioxide CBL are 40.6%and 60.7%higher than that of vertical LEDs without a CBL at 350 mA,respectively.The efficiencies of vertical LEDs without a CBL,with a non-ohmic contact CBL and with a silicon dioxide CBL drop to 72%,78%and 85.5%of their maximum efficiency at 350 mA,respectively. Moreover,vertical LEDs with a non-ohmic contact CBL have relatively superior anti-electrostatic ability.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11204009)the Natural Science Foundation of Beijing,China(Grant No.4142005)
文摘A new epitaxial structure of AlGaInP-based light-emitting diode（LED） with a 0.5-μm GaP window layer was fabricated. In addition, indium tin oxide（ITO） and localized Cr deposition beneath the p-pad electrode were used as the current spreading layer and the Schottky current blocking layer（CBL）, respectively. The results indicated that ITO and the Schottky CBL improve the total light extraction efficiency by relieving the current density crowding beneath the p-pad electrode. At the current of 20 mA, the light output power of the novel LED was 40% and 19% higher than those of the traditional LED and the new epitaxial LED without CBL. It was also found that the novel LED with ITO and CBL shows better thermal characteristics.
文摘The light output power of an InGaN/GaN light-emitting diode is improved by using a SiO2/TiO2 distributed Bragg reflector （DBR） and an A1 mirror as a hybrid reflective current blocking layer （CBL）. Such a hybrid reflective CBL not only plays the role of the CBL by enhancing current spreading but also plays the role of a reflector by preventing photons near the p electrode pad from being absorbed by a metal electrode. At a wavelength of 455 nm, a 1.5-pair of SiO2/TiO2 DBR and an A1 mirror （i.e. 1.5-pair DBR＋A1） deposited on a p-GaN layer showed a normal-incidence reflectivity as high as 97.8%. With 20 mA current injection, it was found that the output power was 25.26, 24.45, 23.58 and 22.45 mW for the LED with a 1.5-pair DBR＋AI CBL, a 3-pair DBR CBL, SiO2 CBL and without a CBL, respectively.
基金Project supported by the National High Technology Research and Development Program of China(No2008AA03A197)the Knowledge Innovation Program of ISCAS(No08S4060000)
文摘A GaN vertical light emitting diode（LED）with a current block layer（CBL）was investigated.Vertical LEDs without a CBL,with a non-ohmic contact CBL and with a silicon dioxide CBL were fabricated.Optical and electrical tests were carried out.The results show that the light output power of vertical LEDs with a non-ohmic contact CBL and with a silicon dioxide CBL are 40.6%and 60.7%higher than that of vertical LEDs without a CBL at 350 mA,respectively.The efficiencies of vertical LEDs without a CBL,with a non-ohmic contact CBL and with a silicon dioxide CBL drop to 72%,78%and 85.5%of their maximum efficiency at 350 mA,respectively. Moreover,vertical LEDs with a non-ohmic contact CBL have relatively superior anti-electrostatic ability.
