Stanford Electrical Engineering

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Physical Technology & Science

Complex electronic systems are ubiquitous (e.g., planes, cars, communication networks, cellphones). At present, there is a pressing need to improve by orders of magnitude the performance and efficiency of existing electronic systems which are the backbones of the information society. At the same time, we are seeing expanding needs in emerging areas such as distributed power networks, electric cars, biomedical devices and systems, and sensor networks.

We are now capable of building things with properties that come from their structure (metamaterials, nanophotonics, nanostructures), and we are able to “design” materials starting from a set of desired properties. The use of these new materials and material properties to build new devices (photonic, electronic, nanoelectromechanical systems (NEMS), and quantum devices) presents many exciting opportunities for research.

Our research in the area of Physical Technology and Science is looking to define the device technology and circuit fabric of future electronic systems. It integrates the abstraction levels of materials, nanostructures, devices, integrated circuits, power electronics and electronic system engineering. Within this setting, we emphasize interdisciplinary research that closely connects emerging device concepts to circuit design and application needs.

 

Physical Technology & Science Sub-Areas:

Bio-Sensing Devices

Faculty members in this area apply electronics, magnetics, photonics, sensors, circuits, and algorithms to measure and alter biological properties. Applications include measuring molecular concentrations, measuring and altering activity of electrically-excitable cells such as neurons, implantable bio-sensors and bio-stimulators, DNA sequencing, THz imaging, differential phase contrast X-ray imaging, wireless sensing and powering,  and the operation of the cardiovascular and nervous systems. Applications range from basic biological science through clinical medicine, and enable new discoveries, diagnoses, and treatments by creating novel devices, systems, and analyses.

Circuits

Faculty in this area work on the design of electronic circuits and systems from low frequencies to mm-wave and THz. Our research is application driven and incorporates a wide range of technologies ranging from emerging nano and MEMS devices, nano-CMOS and BiCMOS processes, as well as discrete electronics for power conversion. Specific research areas include:

  • Mixed-signal integrated circuit design (data converters, sensor interfaces, imaging and selected areas of bio-instrumentation);
  • RF and mm-wave integrated circuit design (wideband communication systems, microwave and millimeter-wave imaging, phased arrays, integrated antennas);
  • Power electronics (switch-mode converters, resonant converters, automotive applications)
  • Analog and digital circuit design for emerging nanotechnologies, including aspects of design methodology, validation and test, and robust circuits and systems;
  • Silicon technology modeling both for digital and analog circuits, including optoelectronic/RF applications, bio-sensors and computer-aided bio-sensor design, wireless implantable sensors.

Energy Efficient Devices

The majority of electronics today are fundamentally limited by the energy they consume. This is the case, for example, both for mobile devices which are battery limited and for data centers which consume MW of power and must be co-located with power plants and generators. Conversely, the availability of more varied energy sources would enable functionality and ubiquity of electronics not yet possible today. Lastly, even if power is readily available, some electronics must obey very strict thermal requirements, such as those that come in contact with the human body. Research in this sub-discipline includes:

  • Thermoelectric (nano)materials for thermal energy harvesting;
  • Circuit integration of power sources with sensors and mobile electronics;
  • Fundamental research into the nanoscale physics of electron-phonon energy interaction;
  • Heat-sensitive electronics and their interaction with strict temperature environments such as car engines (high temperature), the human body (narrow temperature range), or extraterrestrial applications (low temperature);
  • Energy harvesting from vibrations (piezoelectrics), light (photovoltaics, also see Photonics area), Thermo-acoustic energy conversion, and chemical reactions.

Electronics

Research in this area explores new and innovative materials, structures, process, and design technologies for nanoelectronics, energy, environment, and bio-medical applications. This includes:

  • Silicon, germanium, and III-V compound semiconductor devices, metal gate/high-k MOS, and interconnects for nano electronics;
  • Device applications of new materials such as carbon (carbon nanotube, graphene), two-dimensional (2D) layered materials (e.g. MoS2) and semiconductor nanowires;
  • Memory devices such as Flash, phase change memory, metal oxide resistive switching memory;
  • New fabrication technologies for scaling logic and memory devices into the nanometer regime,  three-dimensional (3D) integrated circuits (ICs) with multiple layers of heterogeneous devices, metal and optical interconnections;
  • Compact modeling, technology computer aided design (TCAD), and ab initio modeling of electronic materials and devices;
  • Magnetic nanotechnologies and information storage.

Nanotechnology and MEMS

Nano- and micro-electromechanical systems (NEMS/MEMS) are useful for applications ranging from chemical sensors to relays and logic devices. Research in this sub-area includes:

  • The design of MEMS accelerometers, gyroscopes, electrostatic actuators, and microresonators;
  • Interfacial engineering for NEMS/MEMS;
  • Biosensors, magnetic biochips, in vitro diagnostics, cell sorting, magnetic nanoparticles, spin electronic materials and sensors, magnetic inductive heads, and magnetic integrated inductors and transformers;
  • Flexible substrates for electronics, sensors, and energy conversion platforms;
  • Nanofabrication and nanopatterning technologies, including self-assembly for device fabrication.

Photonics

Faculty in this area investigate physics, materials, devices, and systems using light and electromagnetism generally, for applications including sensing, imaging, communications, computing, energy, biology, medicine, security, and information processing. Their scientific work ranges from basic quantum mechanical processes in nanostructures to planetary science, incorporating technologies from nano and micro scale fabrication through radio and optical fiber communications to environmental probes.

Research areas in this sub-discipline include:

  • Photonics: devices, systems and applications involving electromagnetic waves, in particular light. Applications include communicating information, where photonics plays a crucial role; medical instrumentation; imaging, sensing, and (photovoltaic) solar power generation.
  • Nanoscience and Engineering: physics of nano-photonic structures (where the minimal feature sizes are at the single wavelength or even deep subwavelength scales); controllable fabrication of nanophotonic materials and structures; and the applications of such structures in low-energy information processing and communications, high-efficiency energy conversion, sensing, and medicine
  • Quantum Technologies: study and employment of quantum mechanical properties of light and matter for applications including secure communications, quantum and classical computing, and sensing. Nanophotonics and nanoscience play crucial roles in building a platform for quantum technologies.

 

Active Faculty:

Amin ArbabianBill DallyRobert Dutton, Audrey Ellerbee, Jonathan Fan, Shanhui Fan, James Harris, Lambertus HesselinkMark HorowitzRoger Howe, Joseph Kahn, Butrus Khuri-YakubThomas Lee, David MillerSubhasish MitraBoris MurmannYoshio Nishi, Eric Pop, Piero Pianetta, James PlummerAda Poon, Juan Rivas, Krishna Saraswat, Krishna Shenoy, Olav Solgaard, Jelena VuckovicShan WangH.-S. Philip Wong, Simon Wong, Yoshihisa Yamamoto, Howard Zebker