CdSe quantum dot formation induced by amorphous Se

The mechanism allowing the transition from a two-dimensional strained layer of CdSe on ZnSe to self-assembled islands induced by the use of amorphous selenium is still not fully understood. For a better understanding, atomic force microscopy and transmission electron microscopy studies were performed on CdSe films with a thickness close to that for quantum dot formation. Below this thickness, the sample surface results in undulations along the [1 1 0] crystal direction, while few quantum dots are situated in the wave valleys. Plan view transmission electron microscopy studies reveal a strong anisotropy of the islands and show that the Se desorption conditions are crucial.