<b>CM-AMO Seminar</b><br><i>Focused-Ion Beam Assisted Epitaxy of Hybrid Multifunctional Materials</i>

Speaker: Rachel Goldman (U-M Physics)

To keep pace with increasing demands for performance and functionality of solidstate electronic, optoelectronic, and photonic devices, unprecedented design and control of surfaces and interfaces of hybrid materials at the atomic level during fabrication is needed. Thus, we are developing new directed self-assembly methods for hybrid multi-functional materials, using focused-ion-beam (FIB) assisted molecularbeam epitaxy (MBE). On III-V semiconductor surfaces, FIB irradiation leads to preferential sputtering of group V elements, forming nanoscale group III-rich FIB-milled regions. With continued irradiation beyond a threshold ion dose, group III-rich droplets are observed. In some cases, we use the nanoscale group III-rich regions for the preferential precipitation of nanocrystals in a matrix, termed “FIB-directed matrix seeding”. In other cases, we use surface group III-rich droplets for the growth of quantum dots, via FIB-directed droplet epitaxy, or for nanowires, via a FIB-directed vapor-liquid-solid growth mode. Finally, we are exploring the overgrowth of group III-rich droplets in order to fabricate 3D negative index metamaterials (NIMs), which selectively operate within the infrared and visible frequency ranges. We will present these results and discuss progress towards the design and fabrication of three-dimensional arrays using FIB-assisted MBE.

This work is supported in part by AFOSR, ARO, DOE, NSF, and Intel Corporation.