Optical and electrical characteristics of GaN vertical light emitting diode with current block layer

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.     

垂直结构GaN基LEDs热压键合应力损伤分析

热压键合是垂直结构LED制备的关键工艺步骤,通过TEM,PL,Raman等测试手段,探讨热压键合造成的应力损伤、GaN材料缺陷、LED内量子效率以及反向漏电间的内在联系,研究以键合引起的应力诱导垂直结构GaN基LED光电特性的退化机制,探讨应力损伤对垂直结构GaN基LED光电特性的影响.实验结果表明,热压键合过程会在GaN材料内产生GPa量级的残余应力,在量子限制strark效应作用下,GaN材料辐射复合效率发生明显退化;同时热压键合应力还会诱发GaN材料位错密度的增加,最终导致LED反向漏电增大.     

基于选择性湿法粗化方法制作n型欧姆接触的垂直结构发光二极管的电学性能研究

低阻和高稳定性的氮极性面N型欧姆接触对于GaN基垂直结构发光二极管尤为重要。研究发现,相对于未湿法粗化N型GaN面,湿法粗化N型GaN面的欧姆接触电阻较大,且最终制成的发光二极管具有较高的开启电压和较低的反向漏电。本文提出了一种选择性湿法粗化方法制作氮极性面N型GaN欧姆接触,基于此方法最终制成的垂直结构发光二极管具有更低的开启电压和反向漏电,并且输出光功率略有提升。进一步的老化实验表明该法制作的欧姆接触具有良好的稳定性。     

Electrical characteristics of a vertical light emitting diode with n-type contacts on a selectively wet-etching roughened surface

Low resistance and thermally stable n-type contacts to N-polar GaN are essentially important for vertical light emitting diodes(VLEDs).The electrical characteristics of VLEDs with n-type contacts on a roughened and flat N-polar surface have been compared.VLEDs with contacts deposited on a roughened surface exhibit lower leakage currents yet a higher operating voltage.Based on this,a new scheme by depositing metallization contacts on a selectively wet-etching roughened surface has been developed.Excellent electrical and optical characteristics have been achieved with this method.An aging test further confirmed its stability.     

Effects of the p-AlInGaN/GaN superlattices’structure on the performance of blue LEDs

The advantages of the p-AIInGaN/GaN superlattices＇ （SLs） structure as an electron blocking layer （EBL） for InGaN blue light-emitting diodes （LEDs） were studied by experiment and APSYS simulation. Elec- troluminescence （EL） measurement results show that the LEDs with the p-AllnGaN/GaN SLs＇ structure EBL ex- hibited better optical performance compared with the conventional A1GaN EBL due to the enhancement of hole concentration and hole carrier transport efficiency, and the confinement of electrons＇ overflow between multiple quantum-wells （MQWs） and EBL.     

具有电流阻挡层的垂直结构氮化镓发光二级管的光电特性研究

本文对具有电流阻挡层（CBL）的氮化镓垂直结构发光二极管（LED）进行了研究。不带有CBL、带有非欧姆接触CBL和带有二氧化硅CBL的垂直LED芯片样品被制作出来,并对它们进行了光电性能的测试。结果表明这种带有非欧姆接触CBL和带有二氧化硅CBL的氮化镓垂直结构LED的光输出效率相比不带有CBL的分别高出40.6%和60.7%。不带有CBL的、带有非欧姆接触CBL和带有二氧化硅CBL的氮化镓垂直结构LED在350毫安下的效率分别下降到各自最高效率的72%、78%和85.5%。另外,带有非欧姆接触CBL的氮化镓垂直结构LED具有更优越的抗静电性能。