GaN-based violet laser diodes grown on free-standing GaN substrate

A violet laser diode (LD) structure is grown on afree-standing c-plane GaN substrate and 4~μ m× 800~μm ridge waveguide LDs are fabricated. The electrical and theoptical characteristics of LDs under different facet-coating andchip-mounting conditions are investigated under pulse modeoperation. The active region temperatures of p-side up and p-sidedown mounted LDs are calculated with different injection currents.The calculated thermal resistances of p-side up and p-side downmounted LDs are 4.6~K/W and 3~K/W, respectively. The thresholdcurrent of the p-side down mounted LD is much lower than that of the p-sideup mounted LD. The blue shift of the emission wavelength with increasinginjection current is observed only for the LD with p-side down mountingconfiguration, due to the more efficient heat dissipation.