Metal-organic vapour phase epitaxy: A thin film technology for large-scale production of high power GaAs/GaAlAs laser diodes

Abstract

GaAs/GaAlAs heterostructures grown by metal-organic vapour phase epitaxy are the basic materials for the fabrication of highly sophisticated high power laser devices with wavelengths from 780 to 880 nm. The high power requirements can easily be satisfied by using quantum well (QW) structures with special waveguiding characteristics (SQW, DQW or MQW graded index separate confinement heterostructures). All parameters concerning the morphology and composition of the layers and the electrical and optical behaviour of the multilayer structures should be optimized for large area growth. Devices based on QW materials with well widths as low as 5 nm and thickness variations of only a few atomic layers over an area of 20 cm2 have been realized. Optical output powers under continuous wave operation of more than 1 W from a lateral spot size of 60 μm and more than 2 W from a lateral spot size of 200 μm are measured. With index-guided laser structures up to 50% overall efficiencies in pulsed operation are found.