Articles you may be interested inGrowth of single crystalline GaN thin films on Si(111) substrates by high vacuum metalorganic chemical vapor deposition using a single molecular precursor

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We have investigated the performance of GaN-based blue light-emitting diodes (LEDs) with a p-InGaN/GaN short-period superlattice (SPS) contact layer, which were grown by metal organic chemical vapor deposition. It was found that dot-like features appeared on the surface when a p-InGaN/GaN SPS structure was grown. The LED operating voltage decreased from 3.52 V to 3.15 V and the electrostatic discharge properties of LEDs were improved by using such a SPS structure. The output powers of LEDs were also increased by adjusting the In mole fraction in the SPS. However, the lifetime of LEDs became shorter when such a SPS structure was used.

We have studied the properties of blue-LED wafers grown on GaN with similar dislocation density and different surface flatness. Results indicate that the smooth surface morphology of the undoped GaN layer leads to better layer periodicity in multiple quantum well (MQW) and smooth surface morphology of LED wafers. The surface flatness of the undoped GaN layer has little effect on the forward voltage and output power of the LED. However, the reverse leakage current and the lifetime of the LED wafer grown on the flatter GaN layer improved evidently. On the other hand, wafers grown on the GaN layer with worse surface flatness show better electrostatic discharge (ESD) characteristics.