Author Archives: hassid

Doping of 2D materials

Two-dimensional (2D) semiconductors, such as MoS2 and WSe2, have opened new possibilities for nanoelectronics, heterogeneous integration, optoelectronics, and sensors. However, a stable and controllable doping technique is not yet available for 2D semiconductors. It was recently observed that certain oxides deposited on top of 2D materials dope the 2D layer. In this project we study this intriguing effect of oxide-doping of monolayer 2D materials. We aim to quantify how the stoichiometry and defects in the oxides affect the doping and how it can be tuned.

2D doping cartoon

RF switches with resistive memory devices

High-performance RF switches are important building blocks for reconfigurable radios, where connections between the different blocks are switched to provide services for distinct frequency bands. Resistive memory technologies, such as redox and conductive-bridge RAM (ReRAM, CBRAM), and phase change materials (PCM) are being extensively studied for non-volatile memory applications but have recently been proposed for RF switches. These devices show promising RF figure of merit, non-volatility, fast and low-energy switching and compatibility with back-end-of-the-line (BEOL) of standard CMOS process.

Collaboration with Prof. Shahar Kvatinsky, Technion EE.


Energy efficiency of phase change memory

Phase change memory (PCM) is an important storage-class memory technology and a promising candidate for neuromorphic applications. PCM is based on the reversible resistance change in chalcogenide glasses, like Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> (GST), which can be induced with Joule heating pulses. However, PCM suffers from relatively large programming energy during the reset (amorphization) process which requires heating the PCM above its melting temperature (T<sub>M</sub> ~ 600°C in GST). Reductions in reset energy have so far been achieved mainly by scaling down cell dimensions. We study the fundamental limits of PCM technology by manipulating the cell structure, materials and programming scheme.

<img class=”alignnone size-medium wp-image-118″ src=”/files/2019/05/PCM_energy-300×235.jpg” alt=”PCM energy” width=”300″ height=”235″ />

Memristive 2D materials for neuromorphic

We are trying to develop electronic devices that can emulate the behavior of biological synapses (e.g. short- and long-term plasticity learning rules). It was recently shown that (vertical) devices based on layered (2D) materials can operate in volatile and non-volatile resistive switching modes, corresponding to short- and long-term plasticity.

Collaboration with Prof. Mario Lanza.

Thermometry of electronic devices

We study heat dissipation in electronic devices. Heat and power dissipation limit the performance of state-of-the-art transistors for logic, power and RF applications. Such limitations become more severe in 2D materials and heterogeneous integration. Thermometry is also crucial to understand the principle of operation of thermally activated devices, such as most emerging resistive memory and threshold switching technology.

Raman thermometry