PHOTOLUMINESCENCE STUDIES OF In_0.25Ga_0.75As-GaAs STRAINED QUANTUM WELLS UNDER HIGH PRESSURE

We report the results of the photoluminescence (PL) studies of the In_0.25Ga_0.75As-GaAs strained quantum wells (QW's) at 77K and at high pressures up to 50kbar. The pressure coefficients of the X valley of (InGa)As-GaAs strained QW's are presented for the first time. The crossover between the energy level in the well and the X valley in the barrier GaAs has been observed. The ratio of the conduction band offset to valence band offset in In_0.25Ga_0.75As-GaAs heterojunction was determined to be Q_c=ΔE_c :ΔE_v =0.68:0.32. Some discussions about GaAS – Al_0.3Ga_0.7 As QW's are also presented.