应力释放对InGaN/GaN量子阱有源区发光特性的影响机制OA

Two different green-emitting InGaN/GaN quantum well(QW)structures,with and without a strain-relieving layer,were prepared,and their injection current-dependence of electroluminescence(EL)and temperature dependence of photoluminescence(PL)were investigated.The EL measurements indica-ted that,comparing with the QW structure without a strain-relieving layer(S1),the QW structure with a strain-relieving layer(S2)exhibits a stronger EL intensity,a significant energy redshift,and a smaller ef-ficiency droop.In contrast,the PL measurements indicated that S2 has fewer non-radiative centers,a lar-ger activation energy,and a higher internal quantum efficiency than S1.These results reflected the fact that the introduction of the strain-relieving layer not only relieves the stress in the active region and en-hances the incorporation of Indium atoms,but also improves the structural quality of the active region,strengthens the carrier localization effect,and suppresses electron leakage.Such explanation is consistent with the high-resolution X-ray diffraction measurements,which have shown that S2 has a less dislocation density and better structural/crystalline quality than S1.