Publications by Teodor Rosca | EPFL Graph Search

Millimeter-wave to near-terahertz sensors based on reversible insulator-to-metal transition in VO2

Mihai Adrian Ionescu, Teodor Rosca, Fatemeh Qaderi Rahaqi

In the quest for low power bio-inspired spiking sensors, functional oxides like vanadium dioxide are expected to enable future energy efficient sensing. Here, we report uncooled millimeter-wave spiking detectors based on the sensitivity of insulator-to-met ...

SPRINGERNATURE2023

Static and Dynamic Stochastic Analysis of a Temperature-Sensitive VO2 Spiking Neuron

Mihai Adrian Ionescu, Teodor Rosca

In this work, we investigate the intrinsic cycle-to-cycle variations in a spiking temperature-sensitive neuron, based on the resistive switching of a Vanadium dioxide (VO2) two-terminal device. We study how this phenomenon impacts the spike rate jitter, an ...

IEEE2023

Energy Efficient Sensing using Steep Slope Devices

Teodor Rosca

Today, we are witnessing the Internet of Things (IoT) revolution, which facilitates and improves our lives in many aspects, but comes with several challenges related to the technology deployment at large scales. Handling ever growing amounts of information ...

EPFL2022

Spike-Based Sensing and Communication for Highly Energy-Efficient Sensor Edge Nodes

Mihai Adrian Ionescu, Teodor Rosca

Highly energy-efficient wireless sensor nodes are a prerequisite for a sustainable operation of the Internet of things. Therefore, classical approaches for system design based on digital signal processing are not a viable solution, but system design has to ...

IEEE2022

Intrinsic switching in Si-doped HfO2: A study of Curie-Weiss law and its implications for negative capacitance field-effect transistor

Igor Stolichnov, Mihai Adrian Ionescu, Teodor Rosca, Ali Saeidi, Matteo Cavalieri, Eamon Patrick O'Connor, Carlotta Gastaldi, Sadegh Kamaei Bahmaei

HfO2-based ferroelectrics are considered a promising class of materials for logic and memory applications due to their CMOS compatibility and ferroelectric figures of merit. A steep-slope field-effect-transistor (FET) switch is a device for logic applicati ...

AMER INST PHYSICS2021

High Tuning Range Spiking 1R-1T VO2 Voltage-Controlled Oscillator for Integrated RF and Optical Sensing

Mihai Adrian Ionescu, Teodor Rosca, Fatemeh Qaderi Rahaqi

In this work we propose and experimentally validate a relaxation spiking oscillator architecture with ultra-high tuning range (higher than 400%, from 5KHz to more than 25kHz when the control voltage is varied from 2.5 to 5V) that exploits the reversible me ...

IEEE2021

High Tuning Range Spiking 1R-1T VO2 Voltage-Controlled Oscillator for Integrated RF and Optical Sensing

Mihai Adrian Ionescu, Teodor Rosca, Fatemeh Qaderi Rahaqi

In this work we propose and experimentally validate a relaxation spiking oscillator architecture with ultra-high tuning range (higher than 400%, from 5KHz to more than 25kHz when the control voltage is varied from 2.5 to 5V) that exploits the reversible me ...

IEEE2021

An Experimental Study Of The Photoresponse Of 1T-1R Oscillators Based On Vanadium Dioxide: Towards Spiking Sensing Systems

Mihai Adrian Ionescu, Olivier Martin, Teodor Rosca, Fatemeh Qaderi Rahaqi, Marco Riccardi

In this work we investigate the effect of visible light radiation on compact 1T-1R relaxation spiking oscillator cells based on 2-terminal Vanadium dioxide (VO2) structures. We illuminate the devices using a tunable wavelength laser between 400 and 850 nm ...

IEEE2021

Gate energy efficiency and negative capacitance in ferroelectric 2D/2D TFET from cryogenic to high temperatures

Mihai Adrian Ionescu, Teodor Rosca, Ali Saeidi, Matteo Cavalieri, Luca Capua, Carlotta Gastaldi, Sadegh Kamaei Bahmaei

We report the fabrication process and performance characterization of a fully integrated ferroelectric gate stack in a WSe2/SnSe2 Tunnel FETs (TFETs). The energy behavior of the gate stack during charging and discharging, together with the energy loss of a ...

NATURE PORTFOLIO2021

Nanowire Tunnel FET with Simultaneously Reduced Subthermionic Subthreshold Swing and Off-Current due to Negative Capacitance and Voltage Pinning Effects

Igor Stolichnov, Mihai Adrian Ionescu, Teodor Rosca, Ali Saeidi, Matteo Cavalieri

Nanowire tunnel field-effect transistors (TFETs) have been proposed as the most advanced one-dimensional (1D) devices that break the thermionic 60 mV/decade of the subthreshold swing (SS) of metal oxide semiconductor field-effect transistors (MOSFETs) by u ...

AMER CHEMICAL SOC2020

Radio-Frequency Characteristics of Ge-doped Vanadium Dioxide Thin Films with Increased Transition Temperature

Igor Stolichnov, Mihai Adrian Ionescu, Andreas Schueler, Teodor Rosca, Anna Krammer, Riyaz Mohammed Abdul Khadar, Matteo Cavalieri, Fatemeh Qaderi Rahaqi, Andrei Müller

This work investigates and reports on the radio-frequency (RF) behavior in the frequency range of 5 – 35 GHz of germanium-doped (Ge-doped VO2) vanadium dioxide thin films, deposited on silicon substrates via sputtering and pulsed laser deposition (PLD) wit ...

2020

Sensing device for sensing minor charge variations

Mihai Adrian Ionescu, Cem Alper, Teodor Rosca

A charge sensing device for sensing charge variations in a charge storage area includes: a TFET having at least one sense gate; and a capacitive coupling for coupling the charge storage area with the sense gate. ...

2019

An Experimental Study of Heterostructure Tunnel FET Nanowire Arrays: Digital and Analog Figures of Merit from 300K to 10K

Mihai Adrian Ionescu, Teodor Rosca, Ali Saeidi

In this work, we experimentally report the figures of merit of state-of-the-art heterostructure Tunnel Field-Effect-Transistor (TFET) arrays from room (300K) down to cryogenic temperature (10K) at supply voltages below 400mV. We demonstrate here, for the f ...

IEEE2018

A Steep-Slope Transistor Combining Phase-Change and Band-to-Band-Tunneling to Achieve a sub-Unity Body Factor

Mihai Adrian Ionescu, Josef Andreas Schuler, Wolfgang Amadeus Vitale, Arnab Biswas, Cem Alper, Emanuele Andrea Casu, Teodor Rosca, Anna Krammer, Qun Zhao

Steep-slope transistors allow to scale down the supply voltage and the energy per computed bit of information as compared to conventional field-effect transistors (FETs), due to their sub-60 mV/decade subthreshold swing at room temperature. Currently pursu ...

Nature Research2017

Van der Waals MoS2/VO2 heterostructure junction with tunable rectifier behavior and efficient photoresponse

Igor Stolichnov, Mihai Adrian Ionescu, Andreas Schueler, Olivier Martin, Arnaud Magrez, Chen Yan, Emanuele Andrea Casu, Teodor Rosca, Nicolò Oliva, Anna Krammer

Junctions between n-type semiconductors of different electron affinity show rectification if the junction is abrupt enough. With the advent of 2D materials, we are able to realize thin van der Waals (vdW) heterostructures based on a large diversity of mate ...

Nature Research2017

Hybrid phase-change — Tunnel FET (PC-TFET) switch with subthreshold swing < 10mV/decade and sub-0.1 body factor: Digital and analog benchmarking

Mihai Adrian Ionescu, Josef Andreas Schuler, Wolfgang Amadeus Vitale, Arnab Biswas, Cem Alper, Emanuele Andrea Casu, Teodor Rosca, Nicolò Oliva, Anna Krammer

In this paper we report the first hybrid Phase-Change - Tunnel FET (PC-TFET) device configurations for achieving a deep sub-thermionic steep subthreshold swing at room temperature and subthreshold power savings. The proposed hybrid device feedbacks the ste ...

IEEE2016