9705064 Dobrowolska This is a renewal proposal to study semiconductor heterostructures. Molecular beam epitaxy (MBE) will be used to fabricate three new semiconductor systems: II-VI self-assembled quantum dots (QDs); diluted magnetic III-V semiconductors; and II- VI semiconductor microcavities. The self-assembled QD project will focus on investigation of CdSe QDs grown on ZnSe. Formation of III-V magnetic systems will be attempted by MBE growth of solid solutions of III-V compounds and Mn chalcogenides (e.g., MnTe). Finally, fabrication of II-VI microcavities will focus on MBE fabrication of distributed Bragg reflectors for ZnSe/ZnCdSe quantum well structures. The above systems will be investigated by photoluminescence spectroscopy, optical absorption, and magneto-optical methods. All three projects address fundamental issues relevant to optoelectronic applications of semiconductor heterostructures. %%% This is a renewal proposal to study semiconductor heterostructures. Thin film systems consisting of alternating layers of dissimilar semiconductors ("heterostructures") play a critical role in technologically important devices, such as light emitting diodes, semiconductor lasers, and sensors. Molecular beam epitaxy is a method of forming such multilayers with unprecedented atomic-scale perfection. The present project will apply this method to three new frontiers: the formation of semiconductor structures on the scale of 100 atoms in all three directions ("quantum dots"); the formation of technologically important magnetic semiconductors whose properties can be varied by magnetic field; and fabrication of "microcavities" of immediate importance to the operation of blue light emitters. Optical studies of these systems are expected to pave the way toward new optoelectronic applications. ***
