Monolithic III–V quantum dot lasers on silicon

Monolithic Si-based light sources have long been pursued for Si photonics. However, Si is a very inefficient light-emitting material because of its indirect bandgap. Monolithic growth of III–V materials on Si has been regarded as a promising approach due to their superior optical and electrical properties. Nonetheless, the deployment of monolithic III–V lasers on photonic integrated circuits is still hampered by the high density of various defects during the crystal growth. For several reasons, the use of III–V quantum dots (QDs) as an active region offers substantial advantages including tolerance to defects, low threshold current density, and temperature-insensitive operation because of the unique confinement characteristic of QDs. Accordingly, a great deal of effort has been made to demonstrate the operation of monolithic III–V QD lasers on Si. This chapter reviews the recent advances of monolithic III–V QD lasers on Si and, discusses the current challenges and future directions.