GaN基微米LED大注入条件下发光特性研究

Study on Luminescence Performance of GaN-based μLEDs under High Injection Level

利用变注入强度的电致发光(EL)测试和数值模拟方法研究了微米LED大注入条件下的发光特性。EL测试结果显示,微米LED(10μm)在工作电流密度高达16kA/cm2时光功率密度输出未饱和,同时不存在明显的由于自热效应引起的发光波长红移。和300μm LED相比,相同注入水平下,10μm LED的EL峰值波长相对蓝移,表明微米LED中存在应力弛豫,10μmLED相对300μm LED应力弛豫大了约23%。APYSY模拟发现,由于应力弛豫和良好的电流扩展,微米LED中电流分布和载流子浓度更加均匀,这种均匀的分布使得微米LED具有高的发光效率,同时能够承受高的电流密度。

The luminescence performance of micro-light emitting diodes（μLEDs） under high injection level was investigated by injection current dependent electroluminescence（EL） and numerical simulations.It is shown in EL measurements that the power output density of μLED（10 μm） seems not saturate under extremely high current density of 16 kA/cm2,and also there is no obvious self-heating-related wavelength redshift under high injection level.The degree of strain relaxation is estimated to be 23% for 10 μm LED based on the blueshift of EL peak under the same injection level as compared to 300 μm LED.APSYS simulations show that the current distribution and carrier concentration are much more homogeneous among the wells for μLED due to strain relaxation and uniform current spreading.These uniform distributions lead to high luminous efficiency and high current density endurance for μLED.