Control of size and density of self-assembled InAs dots on (001)GaAs and the dot size dependent capping process

Control on size and density of self-assembled InAs quantum dots (QDs) grown by molecular beam epitaxy on (0 0 1)GaAs has been performed. By properly adjusting the substrate temperature and the amount of InAs deposition, it is possible to prepare QDs that are similar to 15 nm- similar to 50 nm in diameter, and low 10(8) to mid 10(11)/cm(2) in density. Giant QDs that are typically 50-100 nm in diameter are also formed upon excess InAs deposition, and can act as nanoelectrodes. The capping process of these various QDs by GaAs is size dependent, and with a 5 nm thick cap, the previously reported volcano-like structure are seen only when the giant QDs are present. (C) 1999 Elsevier Science B.V. All rights reserved.