MSE Department Seminar

Conventional rechargeable batteries are formed using slurry-cast electrodes whose random nature and porosity limits both energy density and rate performance. As a general rule, such composite electrodes, consisting of a mixture of active material, solid electrolyte, and often conductive additives exhibit power and energy limitations due to the tortuosity of the ion and electron conduction pathways and lower than ideal energy densities due to the volume and mass of the additives.

An exciting research area in condensed matter and materials physics is the response of matter to ultrafast stimuli, such that the eigenmode oscillation period is relatively long. In ferroic materials, the strongly coupled order parameters (magnetization, polarization, strain) and their highly nonlinear responses to fields (magnetic, electric, mechanical, and thermal) provide additional design flexibility for discovering new fundamental phenomena and new device applications.

Computational approaches are increasingly employed to guide and understand experiments, offering a systematic and accelerated path to materials discovery. Automated ab-initio frameworks like aflow++ have rapidly expanded the volume of materials data, enabling the use of data-science methods for the prediction of new materials. These approaches have been used to study superconductors and thermoelectrics, and have proved fruitful with the discovery of new permanent Heusler magnets, superalloys, high-entropy ceramics, and phase change memory compositions.

Density-functional-theory-based calculations using high-performance computers have made enormous strides in describing the atomic-scale properties of complex materials and structures. In parallel, aberration-corrected scanning transmission electron microscopy (STEM) has reached extraordinary levels of spatial and energy resolution, in both imaging and electron-energy-loss spectroscopy (EELS). Recently, the advent of advanced monochromators has led to very high energy resolution in EELS, enabling atomic-resolution vibrational spectroscopy.

Corrosion is a complex phenomenon involving metallic alloys and the surrounding environment. The various forms of corrosion suffered by metallic materials in aqueous environments have been extensively studied and codified. In contrast, studies of corrosion at high temperatures involving gaseous environments, liquids like molten salts, and solid deposits are more limited. There is, however, continued need for studies in this area due to their impact on a broad range of industries including those in the aerospace, power generation, chemical process, and petrochemical refining sectors.

Antiferromagnets represent a new opportunity for developing spintronics with superior speed and high device density. With zero net magnetic moment, they are immune to almost any external magnetic field disturbance. Meanwhile, the intrinsic dynamics at the Terahertz frequency makes them good candidates for high speed electronics. While a lot of useful ways have been developed for manipulating spins in ferromagnets over the past decades, people’s knowledge on detecting and controlling antiferromagnetic ordering remains very limited.

Nanotechnology and nanoscale fabrication techniques have held promise for a wide range of research areas. Beyond traditional microelectronics applications, a wealth of new materials, structures and devices have impacted biology, medicine, chemistry and the physical sciences. My research group, located at the Albany Nanotech Complex, leverages both small scale (200mm wafer scale and smaller) fabrication methods and large scale (300mm wafer scale) approaches to developing new technologies for biosensing and bio-inspired electronics.

Conventional rechargeable batteries are formed using slurry-cast electrodes whose random nature and porosity limits both energy density and rate performance. As a general rule, such composite electrodes, consisting of a mixture of active material, solid electrolyte, and often conductive additives exhibit power and energy limitations due to the tortuosity of the ion and electron conduction pathways and lower than ideal energy densities due to the volume and mass of the additives.

A novel potassium phospho-aluminosilicate (KPAS) glass composition is described that can be strengthened by water vapor to achieve deep compressive stress profiles. This material was initially discovered through a series of hydration experiments in which the KPAS specimen achieved a 29 micron compressive depth after being held in a 85oC, 85% relative humidity chamber for 65 days, thus exhibiting diffusivity orders of magnitude greater than comparative glasses.

Electronic defects within the band gap of semiconductor materials play critical roles in determining the efficiency and stability of their photovoltaic devices. Eliminating deleterious defects in semiconductors or passivating them during the fabrication process of solar cells has become one of the most fundamental tasks for the solar cell society.