High power blue–violet InGaN laser diodes grown on bulk GaN substrates by plasma-assisted molecular beam epitaxy

Abstract

We report on the InGaN multi-quantum well laser diodes (LDs) made by RF plasma-assisted molecular beam epitaxy (PAMBE). The laser operation was demonstrated in a temperature range from 297 K up to 360 K with pulsed current injections using 50 ns pulses at 0.25% duty cycle. The threshold current density and voltage for these LDs were 9 kA cm−2 (680 mA) and 8.2 V respectively at 297 K. The slope efficiency is 0.35–0.47 W A−1. A high output power of 1.1 W was obtained during pulse operation for 3.6 A and 8.7 V. We compare parameters of laser diodes with two and five InGaN/InGaN quantum wells. The new, low temperature growth mechanism which enhances surface adatom kinetics, together with bulk GaN low dislocation density substrates allowed us to grow high quality laser diode structures. Our result indicates that there are no intrinsic limitations in the growth of nitride-based optoelectronic devices by PAMBE.