Performance improvement of 650 nm band AlGaInP laser diodes with optimal diffusion barriers

Abstract

GaInP/AlGaInP multiple quantum-well (MQW) laser diodes with diffusion barriers for Zn, grown by metal organic chemical vapor deposition (MOCVD), were fabricated and characterized. To determine the optimal conditions for the diffusion barriers, we investigated Zn diffusion in the GaInP/(Al 0.5Ga 0.5) 0.5In 0.5P MQW layers against three undoped (Al 0.7Ga 0.3) 0.5In 0.5P diffusion barriers with thicknesses of 0, 90, and 130 nm, respectively, by secondary ion mass spectroscopy (SIMS). Compared to the reference AlGaInP laser diode without a diffusion barrier, the AlGaInP ridge laser with a 130 nm thick diffusion barrier on the top of the MQW layer had a threshold current that was greatly reduced from 110 to 75 mA and the characteristic temperature T o that was increased from 113 to 144 K in the temperature range from 25 to 50 °C. This report presents quantitative information on the effect of Zn diffusion on laser performance.