Broad-area optical characterization of well-width homogeneity in GaN/AlxGa1-xN multiple quantum wells grown on sapphire wafers

We have performed spatially resolved photoluminescence spectroscopy on the entire 2 in. sapphire wafers containing GaN/AlxGa1-xN multiple quantum well s grown by metalorganic chemical vapor deposition. We have observed an ener gy shift of about 50 meV in the ground level emission energy between the ce nter and the peripheric regions of the samples. We show that such a variati on in the emission energy is due to a well narrowing of about 3 ML from the center to the outer regions of the wafers, which induces a large Stark shi ft through the built-in field. (C) 2000 American Institute of Physics. [S00 03-6951(00)01852-0].