Investigation of yellow/green II‐VI compound semiconductor laser diode structures on InP substrates

Abstract

AbstractII‐VI‐compound‐semiconductor laser diode (LD) structures on InP substrates were investigated using device simulations and waveguide analysis. Our simulations showed that electron injection from the n‐cladding into the active layer is hindered by the n‐side barrier layer between the n‐cladding and active layer. Consequently, holes are not injected into the active layer but instead leak to the n‐side layers. It was shown that carrier injection efficiency can be improved by removing the n‐barrier. On the contrary, no large differences were observed between the optical confinement factors of the LD structures with and without the n‐barrier layer. In experiments, we have fabricated the LD structures with and without the n‐barrier layer on InP substrates using molecular beam epitaxy. The turn‐on voltage of the device without the n‐barrier was smaller than that for the device with the n‐barrier by about 5 V. Spontaneous orange emissions around 603 nm were observed for the devices without the n‐barrier. In contrast, no emission was observed for the devices with the n‐barrier. These results prove that the carrier injection into the active layer is enhanced by the removal of the n‐barrier, leading to improved the device performances. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)