RT lasing via nanoscale CdSe islands in a (Zn,Mg)(S,Se) matrix
New approach for high performance lasing in semiconductors using an effect of exciton-induced waveguiding is proposed and realized. We demonstrate RT lasing in a structure without external waveguide formed by cladding of an active region with wider bandgap layers. Stacked arrays of nanoscale CdSe islands inserted directly in a wide bandgap matrix are used as an active media in our case. The lasing wavelength is 460 nm (2.69 eV) at 300K while the bandgap of the matrix material is 2.86 eV, providing an ultimate shift toward blue spectral range for the same matrix material.