Abstract
Optical gain spectra are investigated for Zn
0.7Cd
0.3Se/ZnSe single quantumj well laser structures at room temperature by varying the optical excitation length. An optical gain of several tens of cm
-3 is achieved for 100 kW/cm
2 at the exciton tail region. The photoluminescence excitation spectrum is also measured to determine exciton resonances. The gain mechanism is discussed in terms of phase-space filling of an inhomogeneously broadened exciton state.