GaN垒层厚度渐变的双蓝光波长发光二极管  

Dual-blue Wavelength Light-emitting Diodes Based on Varied GaN Barrier Thickness

作　　者：李正凯[1] 严启荣[1] 罗长得[1] 肖汉章[1] 章勇[1] 

机构地区：[1]华南师范大学光电子材料与技术研究所,广州510631

出　　处：《光子学报》2013年第7期757-762,共6页Acta Photonica Sinica

基　　金：国家自然科学基金(No.U1174001);广东省自然科学基金(No.S2011010003400);广东省科技攻关项目(No.2012B010200032);华南师范大学学生课外科研重点课题项目(No.12GDKC05)资助

摘　　要：针对单蓝光波长芯片与Y3Al5O12∶Ce3+黄光荧光粉封装白光发光二极管存在显色性不足的问题,提出了采用双蓝光波长芯片激发Y3Al5O12∶Ce3+黄光荧光粉实现高显色性白光发射法,并分析了其可行性.利用金属有机化学气相沉积系统在(0001)蓝宝石衬底上顺序生长两个In0.18Ga0.82N/GaN量子阱和两个In0.12Ga0.88N/GaN量子阱的双蓝光波长发光二极管,并对不同GaN垒层厚度的双蓝光波长发光二极管的光电性能进行分析,结果表明沿n-GaN到p-GaN方向减小GaN垒层厚度能实现双蓝光发射,并有较好的发光效率.交流阻抗谱结果显示相关双蓝光波长发光二极管可以用一个电阻Rp与电容Cp并联后与一个Rs串联电路来模拟,GaN垒层变化能调节并联电阻和电容,对串联电阻没有影响.此外,基于垒层减小的双蓝光波长芯片激发Y3Al5O12∶Ce3+荧光粉实现了高显色指数的白光发射.Due to low color rendering index of white light-emitting diodes based on packing of single-blue wavelength chip and Y3A15012 ： Ce3＋ yellow phosphors, using dual-blue wavelength chip, Y3A15012 ： Ce3＋ yellow phoshpor is proposed to realize high color rendering index white emission, and feasibility of the method is analyzed. Dual-blue wavelength light-emitting diodes based on two pairs of In0.18 Ga0. sz N/GaN quantum-well and two pairs of In0.,2 Ga0.88 N/GaN quantum-well structure were grown sequentially on the same sapphire substrate by metal-organic chemical vapor deposition. Optoelectronic properties of dual-wavelength light-emitting diodes with different GaN barrier thicknesses were also studied. The experimental results indicate that efficient dual-blue-wavelength emission and higher luminescent efficiency are realized from light- emitting diodes by reducing GaN barrier thickness from n-GaN to p-GaN. The a. c. impedance spectroscopy can be explained in terms of the equivalent series circuit model of a set of parallel resistor-capacitor RpCp and a resistor Rs for the dual-blue wavelength light-emitting diodes. Varied GaN barrier thickness can tune parallel resistor and capacitor while it has no effect on series resistor. In addition, Y3A15012 ＂ CC＋ phosphor-converted white light emission with high color rendering index is achieved by use of dual-blue emitting active regions from reducing barrier thickness.

关 键 词：GAN 垒层厚度 INGAN GaN量子阱 双蓝光波长 

分 类 号：O242.1[理学—计算数学]