Publications de Jun Ma | EPFL Graph Search

Deep-Learning Reconstruction for 7T MP2RAGE and SPACE MRI: Improving Image Quality at High Acceleration Factors

American Society of Neuroradiology (ASNR)2025

The multimodality cell segmentation challenge: toward universal solutions

Xin Yang, Bo Wang, Yixin Wang, Jun Ma, Lin Han, Maxime Emmanuel Scheder, Marco Labagnara, Sahand Jamal Rahi, Vojislav Gligorovski, Yao Zhang

Cell segmentation is a critical step for quantitative single-cell analysis in microscopy images. Existing cell segmentation methods are often tailored to specific modalities or require manual interventions to specify hyper-parameters in different experimen ...

Nature Portfolio2024

Bacterial inactivation in sunlit surface waters is dominated by reactive species that emanate from the synergy between light, iron, and natural organic matter

César Pulgarin, Stefanos Giannakis, Jun Ma, Da Wang, Shuang Song

In this study, the synergistic and antagonistic effects of Fe species and coexisting natural organic matter (NOM) on the efficacy of solar light disinfection of water are investigated. Different initial iron species (Fe2+/Fe3+) and naturalorganic matter ty ...

Elsevier2023

Multi-channel nanowire devices for efficient power conversion

Elison de Nazareth Matioli, Jun Ma, Vasiliki Tileli, Taifang Wang, Tzu-Hsien Shen, Catherine Erine, Luca Nela

Nanowire-based devices can potentially be of use in a variety of electronic applications, from ultrascaled digital circuits to 5G communication networks. However, the devices are typically restricted to low-power applications due to the relatively low elec ...

2021

P-GaN Tri-Gate MOS Structure for Normally-Off GaN Power Transistors

Elison de Nazareth Matioli, Jun Ma, Minghua Zhu, Pirouz Sohi, Catherine Erine, Mohammad Samizadeh Nikooytabalvandani, Luca Nela

In this letter, we present a new concept for normally-off AlGaN/GaN-on-Si MOS-HEMTs based on the combination of p-GaN, tri-gate and MOS structures to achieve high threshold voltage (V-TH) and low on-resistance (R-ON). The p-GaN is used to engineer the band ...

Institute of Electrical and Electronics Engineers2021

High-Performance Enhancement-Mode AlGaN/GaN Multi-Channel Power Transistors

Elison de Nazareth Matioli, Jun Ma, Catherine Erine, Remco Franciscus Peter van Erp, Luca Nela, Halil Kerim Yildirim

AlGaN/GaN devices have shown outstanding potential for power conversion applications. However, despite the recent progress, their performance is still far from what the material can offer in terms of on-resistance and breakdown voltage. To address this cha ...

IEEE2021

Ultra-compact, high-frequency power integrated circuits based on GaN-on-Si Schottky Barrier Diodes

Elison de Nazareth Matioli, Jun Ma, Georgios Kampitsis, Remco Franciscus Peter van Erp, Luca Nela

GaN transistors are being employed in an increasing number of applications thanks to their excellent performance and competitive price. Yet, GaN diodes are not commercially available and little is known about their performance and potential impact on power ...

2020

Investigation of p-GaN tri-Gate normally-Off GaN Power MOSHEMTs

Elison de Nazareth Matioli, Jun Ma, Minghua Zhu

In this work, we present the investigation of the combination of p-GaN gate and tri-gate structures to achieve normally-off operation on GaN-on-Si MOSFETs. We have developed and optimized a selective and low-damage p-GaN etching recipe to stop at the AlGaN ...

IEEE2020

High-Frequency GaN-on-Si power integrated circuits based on Tri-Anode SBDs

Elison de Nazareth Matioli, Jun Ma, Georgios Kampitsis, Remco Franciscus Peter van Erp, Luca Nela, Halil Kerim Yildirim

In this work, we report on the switching performance of AlGaN/GaN lateral Tri-Anode SBDs. The Tri-Anode architecture leads to a more than 50% reduction in the device charge with respect to conventional planar structure, confirmed both by capacitive and rev ...

IEEE2020

Multi-Channel AlGaN/GaN In-Plane-Gate Field-Effect Transistors

Elison de Nazareth Matioli, Jun Ma, Giovanni Santoruvo, Catherine Erine

In this letter, we present a multi-channel in-plane-gate field effect transistor (MC-IPGFET). In the proposed device, multiple vertically stacked two-dimensional electron gases (2DEGs) are simultaneously controlled by lateral in-plane gates formed with the ...

Institute of Electrical and Electronics Engineers2020

Fast-switching Tri-Anode Schottky Barrier Diodes for monolithically integrated GaN-on-Si power circuits

Elison de Nazareth Matioli, Jun Ma, Georgios Kampitsis, Luca Nela

Tri-Anode GaN Schottky Barrier Diodes (SBDs) have recently shown excellent DC performance with low turn-on voltage and large breakdown thanks to their 3D contact structure around the two-dimensional electron gas (2DEG) channel. However, the 3D nature of th ...

Institute of Electrical and Electronics Engineers2020

High-Voltage Normally-off Recessed Tri-Gate GaN Power MOSFETs With Low on-Resistance

Elison de Nazareth Matioli, Jun Ma, Minghua Zhu, Catherine Erine, Luca Nela

In this letter, we present normally-off GaN-on-Si MOSFETs based on the combination of tri-gate with a short barrier recess to yield a large positive threshold voltage (VTH) while maintaining a low specific on resistance (R ON,SP ) and high current density ...

Institute of Electrical and Electronics Engineers2019

High-performance nanowire-based E-mode Power GaN MOSHEMTs with large workfunction gate metal

Elison de Nazareth Matioli, Jun Ma, Minghua Zhu, Luca Nela

In this work, we demonstrate high-performance Enhancement-mode (E-mode) GaN Metal-Oxide-Semiconductor High Electron Mobility Transistors (MOS-HEMTs) on Si substrate based on sidewall depletion achieved by nanostructured gate with large work-function metal. ...

Institute of Electrical and Electronics Engineers2019

Novel Slanted Field Plate Technology for GaN HEMTs by Grayscale Lithography on Flowable Oxide

Elison de Nazareth Matioli, Jun Ma, Taifang Wang, Luca Nela

We report a novel process to achieve slanted field plate (S-FP), which is a field plate with a gradual increase thickness from gate edge towards drain - utilizing grayscale lithography on flowable oxide (FOX) in single process step, in which developed FOX ...

IEEE2019

High-performance nanowire-based E-mode Power GaN MOSHEMTs

Elison de Nazareth Matioli, Jun Ma, Minghua Zhu, Luca Nela

In this work, we demonstrate high-performance Enhancement-mode (E-mode) GaN Metal-Oxide-Semiconductor High Electron Mobility Transistors (MOS-HEMTs) on Si substrate achieved by a nanostructured gate region in combination with a large work-function gate met ...

IEEE2019

Impact of Fin Width on Tri-Gate GaN MOSHEMTs

Elison de Nazareth Matioli, Jun Ma, Giovanni Santoruvo, Taifang Wang, Luca Nela

In this paper, we present a detailed investigation of the impact of fin width (w(fin)) on tri-gate AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOSHEMTs). As w(fin) is reduced, the threshold voltage (V-TH) increases, which is due ...

2019

Tri-gate technologies for high-performance power GaN devices

Jun Ma

GaN-based electronic devices have great potential for future power applications, thanks to their wide band-gap, high breakdown electric field, and high electron mobility. In addition, these devices can be integrated on large-size Si substrates and enable n ...

EPFL2019

High-performance normally-off tri-gate GaN power MOSFETs

Elison de Nazareth Matioli, Jun Ma, Minghua Zhu, Luca Nela

In this work, we present the investigation of the combination of gate recess and tri-gate structures to achieve high performance normally-off GaN-on-Si MOSFETs with high positive threshold voltage ( VTH ), low specific on resistance ( RON,SP ) and high out ...

IEEE2019

Enhanced mineralization of atrazine by surface induced hydroxyl radicals over light-weight granular mixed-quartz sands with ozone

Stefanos Giannakis, Jun Ma, Da Wang, Shuang Song

A light-weight granular mixed-quartz sand (denoted as L-GQS) combined with stirring-assisted bubble column reactor was firstly applied in catalytic ozonation of atrazine. The L-GQS, with a density of 2.36 g cm(-3) and average diameter of ca. of 4 mm, was r ...

PERGAMON-ELSEVIER SCIENCE LTD2019

1200 V Multi-Channel Power Devices with 2.8 Ω•mm ON-Resistance

Kai Cheng, Elison de Nazareth Matioli, Jun Ma, Minghua Zhu, Catherine Erine, Luca Nela

Here we report novel multi-channel AlGaN/GaN MOSHEMTs with high breakdown voltage (V BR ) and low ON-resistance (R ON ). The multi-channel structure was judiciously designed to yield a small sheet resistance (R s ) of 80 Ω/sq using only four 2DEG channels, ...

IEEE2019