PHOTOLUMINESCENCE AND PHOTOLUMINESCENCE EXCITATION STUDIES OF LATERALSIZE EFFECTS IN ZN1-XMNXSE ZNSE QUANTUM DISK SAMPLES OF DIFFERENT RADII/

Quantum disc structures (with diameters of 200 and 100 nm) were prepar ed from a Zn0.72Mn0.28Se/ZnSe single quantum well structure by electro n beam lithography followed by an etching procedure that combined dry and wet etching techniques. The quantum disc structures and the parent structure were studied by photoluminescence and photoluminescence exc itation spectroscopy. Fdr the light-hole excitons in the quantum well region, shifts of the energy positions are observed following fabricat ion of the discs, confirming that strain relaxation occurs in the pill ars. The light-hole exciton lines also sharpen following disc fabricat ion: this is due to an interplay between strain effects (related to di slocations) and the lateral size of the discs. A further consequence o f the small lateral sizes of the discs is that the intensity of the do nor-bound exciton emission from the disc is found to decrease with the disc radius. These size-related effects occur before the disc radius is reduced to dimensions necessary for lateral quantum confinement to occur but will remain important when the discs are made small enough t o be considered as quantum dots.