Research

Nanowire growth

Nanowires (NWs) are a new material class in the world of semiconductors with potential applications for electronics, photovoltaics, sensors and many other areas. So far, their synthesis using a bottom-up approach has been the most successful these 10 last years since it allowed the combination of materials previously incompatible both axially and laterally. Among the different possibilities, III-V based materials benefit from the most interesting intrinsic properties such as direct bandgaps, high mobilities, and large wavelength coverage. In addition, it has been shown for nanowires based on this semiconductor family that good control can be obtained over their dimension, morphology, position, material combination and crystalline structure.

Schematic of nanowire and nanowire heterostructure growth

(a) Nanowire synthesis through catalyst-mediated axial growth.
(b, c) Switching of the source material results in nanowire axial heterostructure and superlattice.
(d, e) Conformal deposition of different materials leads to the formation of core-shell and core-multishell radial nanowire heterostructures.

Hybrid Materials for Quantum Science and Engineering

The HYBRID project (ANR-PIRE) will establish a multidisciplinary partnership between the University of Pittsburgh, Carnegie Mellon University, University of California, Santa Barbara and France’s Centre National de la Recherche Scientifique (CNRS), Commissariat a l’Energie Atomique (CEA), Universite Grenoble-Alpes and the Grenoble Innovation for New Advanced Technologies campus (GIANT). The aim of this partnership is to facilitate training of students and postdocs centered on the discovery and investigation of materials with particular appeal to the emerging frontiers in fundamental quantum physics and quantum device engineering. In order to explore the potential of hybrid materials for quantum science and technology, this PIRE program will bring together materials engineers, surface scientists, computational chemists, and experimental and theoretical quantum physicists. 

Hybrid materials to be studied are as diverse as core/shell nanowires, van der Waals heterostructures and superconductor-semiconductor epitaxial interface structures. Two dimensional materials will be pursued in the United States, while one-dimensional nanowire-based materials will be the focus of French partners. The approach will extend from in-situ observation of crystal growth to low temperature measurements of quantum devices based on these materials, as well as first-principles and mesoscopic theory studies. Graduate students and postdocs from Pittsburgh and Santa Barbara will perform 2-4 month long research visits to France and participate in international research projects that will take advantage of a well-established GIANT International Internship Program (GIIP), and unique research infrastructure in France including the European synchrotron radiation facility (ESRF), high magnetic field laboratories, molecular beam epitaxy, state of the art materials characterization, nanofabrication and cryogenic facilities. Laboratories in the US will welcome French students for reciprocal visits to take advantage of state-of-the-art infrastructure and unique expertise at the Pittsburgh Quantum Institute, and UCSB molecular beam epitaxy cluster. Topical workshops will be organized to bring together the emerging community of hybrid materials researchers. Summer schools and online courses on the frontier subjects in materials science and quantum computing will be organized for the junior researchers in the program. PIRE:HYBRID will be managed by a U.S.-based executive committee, and overseen by an international advisory board comprised of academic and industrial leaders.

Global scientific and technological goals, especially building quantum computers and simulators put increasingly stringent requirements for quantum coherence on the constituent basic quantum devices and circuits. This motives research into highly crystalline pristine interfaces between different classes of materials. Additionally, new hybrid materials which combine materials such as superconductors and semiconductors will potentially bring new discoveries and new devices. Building a new international partnership focused on addressing this important fundamental challenge will greatly enhance progress in this field by bringing together the intellectual and technological assets of the two countries.

Graduate students and postdocs will be exposed to a unique international and interdisciplinary environment that will enable enhanced training, cross-cultural experiences, and intellectual development. PIRE:HYBRID will partner with industry in the US and Europe to explore the potential applications of new hybrid materials in the context of emerging quantum technologies aimed beyond the CMOS horizon.