The City College of New York
Molecular Beam Epitaxy of Topolgical Insulator Multilayers and Nanostructures
Bi2Se3 and other 3D topological Insulators (TIs) are the subject of much research due to their unique physical properties and potential for novel applications in quantum computing and dissipation less transport. Although many outstanding results have been obtained using bulk crystals, advanced thin film techniques such as molecular beam epitaxy (MBE) may allow large area growth and added control over defect structure and purity. MBE also enables the design and growth of heterostructures for bandstructure engineering, not possible with bulk growth techniques. In spite of the anticipated advantages, the van der Waals nature of the TI materials presents a challenge for the MBE growth of these materials.
I will describe our recent results on the MBE growth and properties of multilayers and nanostructures made from Bi2Se3 and related compounds. These include the growth of Bi2Se3 on various semiconductor substrates, growth of heterostructures of Bi2Se3 and II-VI wide bandgap semiconductors, Bi2Se3/ZnCdSe superlattices as a means to enhance thermoelectric properties, the use of Bi2Se3 /CdTe as a virtual substrate for the growth of II-VI nanostructures on non-compatible substrates, and the growth and properties of Bi2Se3 /Sb2Te3 p-n-p-n superlattices. Finally, I will present our most recent results of the demonstration of 0-dimensional Bi2Se3 quantum dots made by Bi-droplet epitaxy.