(Invited) Nanoscale III-Vs on Oxides and Metals - a Route Towards Low-Cost, High-Performance Electronic and Photonic Devices on Non-Traditional Substrates

Abstract

Pushing the boundaries of electron devices—from transistors to photovoltaics—demands complete control over device architectures and material systems. However, traditional growth and fabrication techniques often fall short when optimal design calls for non-planar geometries or integration of non-epitaxial material systems. Thus, in the past decade, a variety of techniques for X-on-Y growth/integration have been explored. In particular, nanostructures grown via the vapor-liquid-solid (VLS) technique have been studied heavily, demonstrating excellent device performance with the possibility of integrating single crystalline materials with non-epitaxial substrates. However, the stringent restrictions on growth geometry due to the traditional VLS growth mode limits the devices architectures that may be grown and fabricated. Here, a novel method for substrate-agnostic growth of arbitrary geometry III-V materials will be presented as a route towards high performance optoelectronic devices. The direct growth of optoelectronic quality III-V semiconductors on non-epitaxial substrates will be discussed. Structures with geometries varying from the micro/nanoscale single crystalline islands to ultra-large grain polycrystalline thin films may be grown via a thin-film vapor-liquid-solid (TF-VLS) technique. By careful control over nucleation position and shape of III-V semiconductors, arbitrarily shaped single-crystalline islands may be grown on non-epitaxial substrates. First, the general method for this growth will be discussed, illustrating how different structures and geometries may be obtained. Next electronic and optoelectronic characterization of the grown materials will be presented, showing that films display excellent optoelectronic characteristics. Finally, devices fabricated from the grown material will be shown, illustrating that high-performance devices may be obtained without utilizing costly lattice matched substrates.