BAND EDGE OFFSETS IN STRAINED (INGA)AS-(ALGA)AS HETEROSTRUCTURES

The excitonic transitions between the ground electron and hole quantum well sublevels in strained In//xGa//1// minus //xAs-Al//yGa//1// minus //yAs multiple quantum well structures (x equals 0. 12-0. 35 and y equals 0. 2-0. 35) have been investigated by means of photoluminescence and photoconductivity measurements. The molecular beam epitaxy grown structures contained an Al//yGa//1// minus //yAs matrix with one unstrained GaAs and three strained In//xGa//1// minus //xAs quantum wells one of which was in the GaAs cladding layers. The ratio of the conduction band edge line up to the band gap offset for the strained In//xGa//1// minus //xAs-unstrained Al//yGa//1// minus //yAs interface has been found to be 0. 67 plus or minus 0. 08 for the studied regions of x and y.