Carrier transport mechanism of Pd/Pt/Au ohmic contacts to p-GaN in InGaN laser diode

The dependence of contact resistivity on the carrier concentration for the non-alloyed Pd contacts on p-GaN and the temperature dependence measurements of sheet resistivity of p-GaN suggest that carrier transport at the interface between the contact and the p-GaN would be dominated by deep level defect band, rather than the valence band. Based on these results, in order to reduce the operating voltage of the InGaN laser diode (LD), we designed a p-GaN : Mg contact layer, where the ohmic metals are contacted, and optimized the p-GaN contact layer.