Effects of sulfur treatment on electrical and optical performance of InGaN/GaN multiple-quantum-well blue light-emitting diodes

The results of the sulfur treatment of multiple-quantum-well (MQW) light-em itting diodes (LEDs) with (NH4)(2)S and (NH4)(2)S + t-C4H9OH solutions prio r to the deposition of a light-transmitting p-electrode metal are presented . The room-temperature I-V curves showed that the forward voltages of MQW L EDs treated with the two sulfur solutions decrease by 0.12 and 0.35 V at 20 mA, respectively, compared to the untreated MQW LED, as the result of an i mprovement in p-Ohmic contact characteristics. The relative light-output po wer and external quantum efficiency of MQW LEDs increased by a factor of 1. 28 for the (NH4)(2)S treated sample and 2.23 for the (NH4)(2)S + t-C4H9OH t reated sample compared to the untreated sample. In addition, the reverse le akage current characteristic of MQW LEDs was reduced as a result of sulfur treatment. This can be attributed to the passivation of surface and sidewal l damages formed after the dry-etching process for a reliable pattern trans fer. The present results indicate that the sulfur treatment greatly improve s the electrical and optical performance of MQW LEDs. (C) 2001 American Ins titute of Physics.