MBE grown high-quality CdSe-based islands and quantum wells using CdS compound and Se

Using CdS compound and elemental Se, li e have grown CdSc/ZnSe quantum stru ctures with improved optical and structural properties exploiting an exchan ge reaction which leads to the substitution of sulfur by selenium. Typical S contamination is below 2%. A possibly enhanced surface diffusion of adato ms caused by the high CdS oven temperature and a surfactant-like effect of the S-Se exchange lead to a suppression of Cd segregation in the case of mi gration enhanced epitaxy with long Se exposure times. The new growth method leads to CdSe quantum wells with outstanding optical quality. Their proper ties are compared to CdSe island structures obtained in a non-migration-enh anced growth mode. (C) 2001 Elsevier Science B.V. All rights reserved.