InGaN/GaN LEDs with a Si-doped InGaN/GaN short-period superlattice tunneling contact layer

Nitride-based light-emitting diodes (LEDs) with Si-doped n(+)-In0.23Ga0.77N/GaN short-period superlattice (SPS) tunneling contact top layer were fabricated. It was found that although the measured specific-contact resistance is around 1 x 10(-2) Omega-cm(2) for samples with an SPS tunneling contact layer, the measured specific-contact resistance is around 1.5 x 10(0) Omega-cm(2) for samples without an SPS tunneling contact layer. Furthermore, it was found that one could lower the LED-operation voltage from 3.75 V to 3.4 V by introducing the SPS structure. It was also found that the LED-operation voltage is almost independent of the CP2Mg flow rate when we grow the underneath p-type GaN layer. The LED-output intensity was also found to be larger for samples with the SPS structure.