Areas of Expertise (7)
Materials Science and Engineering
Nanoscale and Quantum Science
Physics of Materials
Hull joined Rensselaer in January 2008 to assume the positions of the Head of the Materials Science and Engineering Department and the Henry Burlage Professor of Engineering. Prior to that he spent about a decade at Bell Laboratories in the Physics Research Division, and twelve years at the University of Virginia, where he was the Director of an NSF MRSEC Center and Director of the UVA Institute for Nanoscale and Quantum Science.
He received his PhD in Materials Science from Oxford University in 1983. Hull is highly active in engineering and materials science societies and professional groups. He is a fellow of the American Physical Society and of the Materials Research Society, and in 1997 served as president of the Materials Research Society. He has also chaired a Gordon Research Conference on Thin Films, and chaired the Committee of Visitors for the National Science Foundation’s Division of Materials Research. Within the realms of materials and nanoscience, Hull’s research focuses on the relationships between structure and property in electronic materials, fundamental mechanisms of thin film growth, and the self-assembly of nanoscale structures. Other areas of interest include degradation modes in electronic and optoelectronic devices, the properties of dislocations in semiconductors, nanoscale fabrication techniques, nanoscale tomographic reconstruction techniques, development of new nanoelectronic architectures, and the theory and application of electron and ion beams.
Oxford University: Ph.D., Metallurgy and Materials Science 1983
Oxford University: B.A., Physics 1980
Advanced options in Electronics and Physics of Materials
Media Appearances (3)
Stochasticity–inherent fluctuations in materials merit exploration
Scientists and engineers who work with materials – metals, polymers, ceramics, composites, and glasses – know that at some scale, predictive ability breaks down amid the fluctuations known as "stochasticity." On the atomic scale for example, even the most perfect crystal has thermodynamic fluctuations, in the form of "point defects" – atoms missing from the crystal lattice. In another example, the atoms within an alloy material may distribute in many ways: an alloy made of silicon germanium, may be half and half of each element overall, but with stochastic fluctuations the ratio in which those elements are found varies at different length scales throughout the material.
Rensselaer Professor Emily Liu Receives $1.8 Million DoE Award for Solar Power Systems Research
RPI News online
Li (Emily) Liu, associate professor of nuclear engineering and engineering physics in the Department of Mechanical, Aerospace, and Nuclear Engineering at Rensselaer Polytechnic Institute, has been selected by the U.S. Department of Energy Solar Energy Technologies Office (SETO) to receive a $1.8 million award to study high-temperature molten-salt properties and corrosion mechanisms. This award is part of a $72 million funding program to advance concentrating solar power (CSP) research, a power plant technology that could reduce the cost of solar energy.
Robert Hull Named Director of Center for Materials, Devices, and Integrated Systems at Rensselaer Polytechnic Institute
RPI News online
Troy, N.Y. – Advanced materials leader Robert Hull, the Henry Burlage Jr. Professor of Engineering and head of the Department of Materials Science and Engineering at Rensselaer Polytechnic Institute, has been named the first director of the Institute’s new Center for Materials, Devices, and Integrated Systems (cMDIS). The appointment is effective October 1, 2014.
H. Parvaneh, R. Hull
2014 Ion induced Auger electron spectroscopy is a technique where Auger electrons are produced as a result of energetic ion impact. In this paper, the ion–induced electron spectra of three of the transition metals; Ti, Cr and Co by Si++ and Au+ ions accelerated to 30 and 60 keV are studied. Aside from the low energy plasmon peaks, sharp M23M45M45 Auger transitions with high signal to noise ratio attributed to the metal targets and, in the samples bombarded by Si++ ions, L23MM transition from Si incident ion are also detected. Broad tails next to the main metal Auger peaks are attributed to interatomic transitions between the incident ion and target ions.
P. Balasubramanian, J.A. Floro, J.L. Gray and R. Hull
2014 Epitaxial growth of SiGe alloy films under certain kinetically limiting conditions has previously been shown to lead to the self-assembly of nanostructures called Quantum Dot Molecules, QDMs. These QDMs consist of an assembly of pyramidal pits and elongated pyramidal islands, which exist at the edges of the pits. We investigate the nano-scale chemistry of QDMs in Si0.7Ge0.3/Si (100) using Auger electron spectroscopy (AES). First, our AES analysis indicates that compressively strained QDM pit bases are most Ge rich regions in QDMs, consistent with previously reported observations. Second, our Auger analysis of the QDMs shows that Ge composition continuously increases from outside edges of the islands to the pit cusps. This results in asymmetric distribution of Ge about the apex of the islands. The segregation of Ge to the pit cusps is unexpected on the basis of strain energy minimization, and we propose that it is due to attachment of Ge to steps on the interiors of the QDMs. The continually varying Ge composition towards the pit cusps is also inconsistent with previous observations of islands in GeSi growth, where the composition is reported to be symmetric about the apex of islands.
Li He and Robert Hull
2012 This work investigates the quantification of electron–phonon thermal diffuse scattering (TDS) for detection of temperature variations with nanometer spatial resolution in transmission electron microscopy (TEM). Observations of TDS intensity for (100) single crystal Si and Ge show interdependences of temperature and sample thickness which can be understood through the angular distributions of electron–phonon scattering as a function of temperature. The temperature sensitivity of the integrated TDS intensity can be of the order of 10−3 K−1 for Si and Ge. This shows that measurement of the TDS intensity in the TEM is a promising means for nanoscale temperature measurement; our measurements to date have demonstrated that temperature changes as small as 5 K are detectable.
Xiaowei Wu and Robert Hull
2012 A new high spatial resolution non-contact temperature measurement technique (thermal scanning electron microscopy, ThSEM) is demonstrated. It employs temperature dependent thermal diffuse scattering in electron backscatter diffraction (EBSD) in a scanning electron microscope (SEM). Unlike conventional scanning thermal microscopy, which uses contact probes, ThSEM is a non-contact method. In contrast to optical temperature mapping techniques, ThSEM does not have the spatial resolution limitation that arises from the optical wavelength and theoretically can reach a resolution of
Jessica K. Murphy and Robert Hull
2011 We examine variations in the basic structure of quantum dot molecules (fourfold quantum dot nanostructures forming around a central facetted pit) in the SixGe1−x/Si(100) system. Arrays of quantum dot molecules are seeded by Ga+ focused ion beam (FIB) prepatterning of the Si substrate prior to epitaxial Si buffer layer growth and GexSi1−x film deposition. Five main variants to the regular quantum dot molecule structure are observed. The populations of these variant structures depend on the initial FIB processing conditions; their frequencies generally increase with increasing prepatterned pit depth and with increasing incident ion energy. This work suggests both routes to improving uniformity of regular quantum dot molecule arrays as well as routes to enabling synthesis of a wider range of nanostructure geometries.