Effects of Current, Temperature, and Chip Size on the Performance of AlGaInP-Based Red Micro-Light-Emitting Diodes with Different Contact Schemes

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 similar to 632 and similar to 640 nm, whose intensity depended on the type of contact schemes and temperature. Regardless of the contact schemes, the 10 mu m-size samples showed a larger temperature-dependent reduction in the output power at current density of mu 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-mu m samples was red-shifted, whereas no red-shift was detected in the 10-mu 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.