氮化镓基白光发光二极管的快中子辐照效应

Fast neutron irradiation effects on white Gallium Nitride light-emitting diodes

摘要:

对注入量为1×10¹⁴ cm^-2的快中子(1.2 MeV)对氮化镓(GaN)基白光发光二极管(LED)器件的辐照效应进行研究。通过测量和分析器件的电致发光谱(EL)、光功率-电流(L-I)和电流-电压(I-U)特性，发现器件辐照后光功率降低，而EL谱形状几乎没有变化，表明该注入量的中子辐照主要对器件中的蓝光LED芯片造成了损伤。进一步分析发现，中子辐照导致蓝光LED量子阱中产生大量非辐射复合中心，增加了漏电流并减小了量子阱中载流子密度，从而降低LED的输出光功率。由此，在原有GaN基蓝光LED等效电路模型的基础上，加入由中子辐照导致的影响因素，不仅有助于理解中子辐照对LED光功率的衰退影响机理，还为预测辐照后光功率的变化提供了可行性。

Abstract:

The irradiation effect of fast neutrons(1.2 MeV) on Gallium Nitride(GaN) white Light-Emitting Diodes(LEDs) with fluence of 1×10¹⁴ cm^-2 is reported. The Electroluminescence(EL) spectrum, output power-current(L-I) and current-voltage(I-U) characteristics of the device are measured and analyzed. It is found that the optical output power decreasing after irradiation, while the shape of the EL spectrum almost remains unchanged, indicating that the neutron irradiation mainly causes damage to the blue LED chip. Further analysis shows that neutron irradiation leads to the generation of a large number of nonradiative recombination centers in the quantum well, which increases the leakage current and decreases the carrier density, thus reducing the output power of LED. In addition, the influencing factors caused by neutron irradiation are added to the original equivalent circuit model of GaN-based LEDs. This model not only helps to understand the mechanism of the degradation of the neutron irradiation on the LED output power, but also provides a feasible method to predict the change of the output power after irradiation.