Ali

Research Expertise and Interest

nanotechnology, low power electronics, flexible electronics and sensors, nanofabrication, energy harvesting and conversion, programmable matter

Research Description

Ali Javey is a professor of Electrical Engineering and Computer Sciences.  The core of Javey’s research program is materials innovation for enabling new device structures and concepts. The lab studies a wide range of electronic materials in both planar and 3D geometries. In all cases, the lab explores new schemes of manipulating, processing, and engineering materials - often at unprecedented levels - to enable new functionalities and properties. Below are some research highlights.

  1. Developed a new doping technology named monolayer doping (MLD) that utilizes surface chemistry to form self-assembled monolayers of dopant containing species on semiconductor surfaces followed by a subsequent diffusion by a thermal annealing (Nature Materials, 2008).  The process has yielded some of the shallowest junctions reported to date, down to ~3 nm in thickness. The technology has been transferred to the semiconductor industry for further internal R&D, and is seen as a promising approach for S/D contact extensions for future nanoscale transistors.
  2. Developed the ultrathin body III-V on insulator (XOI) device concept as a platform for integrating high mobility III-V semiconductors on Si for low power electronics (Nature, 2010).  Reported p- and n-type III-V FETs with some of the highest mobilities reported to-date on a Si substrate with a subthreshold swing as low as ~70 mV/decade, approaching the ideal limit of MOSFETs.
  3. Discovered the quantum unit of absorptance in 2D semiconductors (in collaboration with E. Yablonovitch; PNAS, 2013).
  4. Developed a new growth mode for III-V thin films using the vapor-liquid-solid (VLS) technique (Scientific Reports, 2013).  As a proof of concept, InP thin films (on the order of 1µm in thickness) are grown on non-epitaxial substrates (e.g., metal foils) using the thin-film VLS process with an ultralarge grain size of up to ~ 1mm and optoelectronic properties (including luminescence yield) approaching those of epitaxially grown layers. The work presents a promising route for low-cost growth of high quality III-V semiconductors for PV applications and beyond.
  5. Developed process techniques for uniform assembly of nanostructured materials (e.g., nanowires and nanotubes) over large-areas for system integration – moving beyond individual device work (Nature Materials, 2013; Nature Materials, 2010).  As a proof of concept, Javey’s lab has demonstrated large-area monolithic integration of nanotube TFTs, pressure sensors, and OLEDs on a plastic substrate that can map pressure and provide instantaneous visual response through the integrated OLED display.  The work presents a platform for 3-D integration of different material/device components for paper-thin smart/interactive surfaces, and is an elegant example of systems enabled by nanomanufacturing. 

In the News

LED Material Shines Under Strain

Smartphones, laptops, and lighting applications rely on light-emitting diodes (LEDs) to shine bright. But the brighter these LED technologies shine, the more inefficient they become, releasing more energy as heat instead of light. Now, as reported in the journal Science, a team led by researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley has demonstrated an approach for achieving near 100% light-emission efficiency at all brightness levels.

Wearable sensors detect what’s in your sweat

Needle pricks not your thing? A team of scientists at the University of California, Berkeley, is developing wearable skin sensors that can detect what’s in your sweat. They hope that one day, monitoring perspiration could bypass the need for more invasive procedures like blood draws, and provide real-time updates on health problems such as dehydration or fatigue.

Physiological Changes Tracked Moment to Moment

Imbedded in a sweatband, a network of sensors devised by Ali Javey can monitor moment-by-moment changes in electrolytes and metabolites, a potential boon to weekend athletes, diabetics and people exposed to heavy metal concentrations.

Smallest. Transistor. Ever.

For more than a decade, engineers have been racing to shrink the size of components in integrated circuits. Now, a research team at UC Berkeley has surpassed a theoretical limit of physics and created the smallest transistor reported to date.

A New Twist for Nanopillar Light Collectors

UC Berkeley researchers have created unique dual-diameter nanopillars – narrow at the top, broad at the bottom – that absorb light as well or even better than commercial thin-film solar cells, using far less semiconductor material and without the need for anti-reflective coating.

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