EFFECT OF HYDROSTATIC-PRESSURE ON STRAINED CDSE/ZNSE SINGLE QUANTUM-WELLS

The effect of hydrostatic pressure on the quantum confined transition in CdSe/ZnSe single quantum wells grown by molecular beam epitaxy has been studied by low-temperature photoluminescence measurements. Samples with layer thicknesses of CdSe from 1 to 4 monolayers were used. Strong excitonic emissions associated with the lowest GAMMA-GAMMA interband transitions were observed in these highly strained quantum well samples. The pressure coefficients of the interband transitions are found to depend on well thickness with the numerical value decreasing as the well width increases. Pronounced sublinear pressure dependence of the excitonic emissions was observed in the samples with 3 and 4 monolayer CdSe wells, indicating the degradation of the samples due to strain relaxation. Our results suggest that the critical thickness for the CdSe layer pseudomorphically grown on ZnSe is less than 4 monolayers.