Effects of Current, Temperature, and Chip Size on the Performance of AlGaInP-Based Red Micro-Light-Emitting Diodes with Different Contact Schemes. (3rd September 2021) - Lee, Da-Hoon
Abstract : We have investigated the performance of AlGaInP-based red micro-light-emitting diodes (micro-LEDs) with different n-type contact schemes as functions of current, ambient temperature, and chip size. The samples with AuGe/Ni/Au contact revealed wider full width at half maximum of electroluminescence than that with the Pd/Ge contact. All samples also exhibited broad peaks at wavelengths between ∼632 and ∼640 nm, whose intensity depended on the type of contact schemes and temperature. Regardless of the contact schemes, the 10 μ m-size samples showed a larger temperature-dependent reduction in the output power at current density of <50 A cm −2 than the 100 μ m-size ones. Above 100 A cm −2, however, both samples showed similar temperature dependence. Irrespective of the contact schemes, the main peak of the 100- μ m samples was red-shifted, whereas no red-shift was detected in the 10- μ m samples. The third peak of the AuGe-based contact samples became more dominant at 700 A cm −2 than the main peak, whereas that of the PdGe contact samples became more dominant at 1000 A cm −2 . Based on the chip size, current, contact scheme, and temperature dependence, the performance degradation of the red micro-LEDs is described and discussed.