Quantum dot VCSELs

A quantum dot (QD), represents a semiconductor crystal with a size of several nanometers which demonstrates the basic properties of the atom, allowing new types of solid state devices. The possibility of achieving improved and temperature insensitive parameters of a semiconductor laser using QDs was proposed by Arakawa and Sakaki (1982). Later Asada et al. (1986) pointed to a possibility of using ultrahigh material gain in QDs. More than a decade passed until the first QD lasers were fabricated in 1993 and were proven to demonstrate some of the predicted properties. Recently significant interest arose for using QDs as active medium for VCSELs. In the approach lasers with ultralow total currents are fabricated, and, even more exciting, lasers based on a single QD can be potentially realized, as the spreading of nonequilibrium carriers important for small apertures is suppressed.