All-MBE grown InAs/GaAs quantum dot lasers with thin Ge buffer layer on Si substrates
Junjie Yang, Zizhuo Liu, Pamela Jurczak, Mingchu Tang, Keshuang Li, Shujie Pan, Ana M. Sánchez, Richard Beanland, Jinchuan Zhang, Huan Wang, Fengqi Liu, Zhibo Li, Samuel Shutts, Peter M. Smowton, Siming Chen, A.J. Seeds, Huiyun Liu
Abstract
Abstract A high-performance III–V quantum-dot (QD) laser monolithically grown on Si is one of the most promising candidates for commercially viable Si-based lasers. Great efforts have been made to overcome the challenges due to the heteroepitaxial growth, including threading dislocations and anti-phase boundaries, by growing a more than 2 µ m thick III–V buffer layer. However, this relatively thick III–V buffer layer causes the formation of thermal cracks in III–V epi-layers, and hence a low yield of Si-based optoelectronic devices. In this paper, we demonstrate a usage of thin Ge buffer layer to replace the initial part of GaAs buffer layer on Si to reduce the overall thickness of the structure, while maintaining a low density of defects in III–V layers and hence the performance of the InAs/GaAs QD laser. A very high operating temperature of 130 °C has been demonstrated for an InAs/GaAs QD laser by this approach.