Saturation effects in the photoluminescence spectra of Hg0.3Cd0.7Te

The photoluminescence spectrum of Hg_0.3Cd_0.7Te at 77K consists of a narrow, high energy free exciton line D and a broad, low energy deep level E. As a function of incident excitation power, the E line must be saturated before the D line can be observed. We have constructed a simple model that agrees well with the experimental dependences of the luminescence intensities of the D and E lines on excitation power.