Lasing in submonolayer CdSe structures in a ZnSe matrix without external optical confinement

It is shown that in order to achieve lasing in structures with CdSe submonolayers inserted in a ZnSe matrix, no additional optical confinement of the active region using thick wide-gap layers is required. The high oscillator strength of the excitons trapped at CdSe islands modulates the permittivity and thus produces a natural exciton-induced waveguiding effect.