Mg-rich precipitates in the p-type doping of InGaN-based laser diodes

Abstract

Uniformly distributed precipitates have been observed by transmission electron microscopy in the p-type layers of laser structures. The precipitate density decreases with decreasing flow of biscyclopentadienyl-magnesium $({\mathrm{Cp}}_2\mathrm{Mg}\mathrm{),}$ and the hole concentration in the laser structure was higher for a lower precipitate density. The higher hole concentration reduces the threshold current density and improves the internal quantum efficiency of the laser because of the higher number of holes available for radiative recombination. The lasers with higher precipitate density also exhibit a higher resistance. The threshold voltage was reduced 30% from 20.8 V for lasers with a high precipitate density to 14.3 V for lasers with a lower precipitate density due to the lower resistance.