Semiconductors – EmFPecora

February 2, 2014July 1, 2025

My Research on Boron Behavior in Silicon Materials

My research has extensively explored the intricate behavior of boron (B) atoms within both crystalline and amorphous silicon (Si), which is a critical area for semiconductor device fabrication. Understanding how boron moves and organizes itself within silicon is essential for controlling the electrical properties of integrated circuits.

My investigations have focused on unraveling the mechanisms of boron diffusion, providing experimental evidence and theoretical insights into how boron spreads through these silicon structures. A significant part of my work has involved studying boron clustering in amorphous silicon, revealing how boron atoms can group together, which directly impacts their electrical activation and overall device performance. We’ve specifically looked into the concept of indirect diffusion of boron atoms in both crystalline and amorphous silicon, shedding light on the complex pathways these atoms take. This comprehensive research has clarified the fundamental processes governing boron behavior, offering crucial knowledge for optimizing doping profiles and improving the performance and reliability of silicon-based electronic devices.

These projects have been funded partly by Scuola Superiore di Catania.

Peer-reviewed publications

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January 16, 2014July 1, 2025

My Research in Nanowire Growth and Manipulation

My research has extensively explored the fascinating world of silicon (Si) and germanium (Ge) nanowires, focusing on their fundamental growth mechanisms, structural control, and even their mechanical manipulation at the nanoscale. A significant portion of my work has centered on using electron beam evaporation as a precise method for growing these nanowires, allowing us to delve into the kinetics of their growth and achieve heteroepitaxial growth of Ge nanowires directly on Si substrates, including understanding their unique faceting behaviors. I’ve also focused on gaining control over the growth mechanisms and orientation of epitaxial Si nanowires, which is crucial for their integration into future technologies.

Beyond growth, my investigations have unveiled the remarkable properties of these tiny structures under external influences. My work has demonstrated and analyzed nanoscale amorphization, bending, and subsequent recrystallization in silicon nanowires, showing how they react to stress at the atomic level. Furthermore, I’ve specifically studied ion beam-induced bending of silicon nanowires, offering insights into directed manipulation techniques. We’ve also examined the subtle yet critical influence of oxygen contamination and the properties of gold (Au) catalyst clusters on the resulting structural features of Si nanowires, providing a comprehensive understanding of the factors that govern their final form. This body of research collectively contributes to a deeper understanding of nanowire science, paving the way for their application in areas like advanced electronics, sensors, and energy devices.

These projects have been funded partly by University of Catania and CSFNSM (Growth and characterization of Si and Ge nanowires), and performed during my PhD course.

Peer-reviewed publications

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Book / Book chapter

Growth, properties and processing of group IV semiconductor nanowires
E. F. Pecora
VDM Verlag Dr. Muller (August 4, 2011), ISBN: 978-3639375763

January 16, 2014July 1, 2025

My Research in Deep Ultraviolet Light Technology

My research has been dedicated to advancing the field of deep ultraviolet (UV) light technology, specifically focusing on developing high-performance light emitters and lasers using Aluminum Gallium Nitride (AlGaN) materials. I have developed advanced nanostructures—tiny layered crystals—that glow and amplify light in the deep-UV spectrum (around 220–270 nm) at room temperature. By smartly grading the material layers and using ultrathin quantum disks, I’ve:

Emitted UV light as short as 219 nm with strong efficiency (40%)
Reduced structural flaws and improved light confinement
Demonstrated real optical gain and early signs of laser-like behavior

A core aspect of my work involves precisely growing AlGaN multiple quantum well (MQW) structures, often utilizing advanced techniques like molecular beam epitaxy (MBE) on SiC substrates. These sophisticated designs, alongside the deliberate introduction of band-structure potential fluctuations within the AlGaN wells, have led to substantial improvements in device performance, crucial for enhancing light emission and achieving significant optical gain in the critical deep UV spectrum, particularly at wavelengths below 250 nanometers.

I’ve achieved impressive results, including high internal quantum efficiency, significant optical gain (up to 120-140 cm⁻¹), and remarkably low transparency thresholds (as low as 5 µJ/cm²). I have also explored the polarization properties of deep-UV optical gain, observing strong transverse electric (TE)-polarized amplified emission.

This body of work collectively highlights a significant step forward in the quest to develop efficient, room-temperature solid-state deep-UV lasers and light-emitting diodes, opening doors for their use in critical applications such as sterilization, sensing, and advanced communication systems.

This work has been funded by DARPA – Defense Advanced Research Projects Agency CMUVT Program under subcontract from Photon Systems Inc. (2011, March – 2012, March) and performed at Boston University.

Peer-reviewed publications

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Conferences

Sub-250nm room temperature optical gain from AlGaN materials with strong compositional fluctuations
E. F. Pecora, W. Zhang, H. Sun, A. Yu. Nikiforov, J. Yin, R. Paiella, T. D. Moustakas, L. Dal Negro
Bulletin of the American Physical Society, vol. 58, V1.00111

Sub-250nm room temperature optical gain from AlGaN/AlN multiple quantum wells structures
E. F. Pecora, W. Zhang, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, T. D. Moustakas
CLEO: Science and Innovations, CTh3D, CTh3D.5

Sub-250nm room-temperature optical gain from AlGaN/AlN multiple quantum dot structures
E. F. Pecora, W. Zhang, L. Zhou, D. J. Smith, J. Yin, R. Paiella, L. Dal Negro, T. D. Moustakas
Bulletin of the American Physical Society, vol. 57

Room temperature low threshold stimulated emission of electron beam-pumped AlGaN-based deep UV laser structures emitting below 250 nm
A. Nikiforov, W. Zhang, J. Woodward, J. Yin, E. Pecora, L. Zhou, L. Dal Negro, R. Paiella, D. Smith, T. Moustakas, A. Moldawer
Bulletin of the American Physical Society, vol. 57

March 1, 2011July 1, 2025

PostDoc at Boston University

Read my blog posts on my research in deep ultraviolet light technology, my research in light-emitting materials for microphotonics, my research in silicon nanostructures for light emission, and my research in nanophotonic-plasmonic and light-matter interaction.

Research projects

Nanoscale optical Emitters for High Density Information Processing using Photonic-Plasmonic Coupling in Coaxial Nanopillars, funded by AFOSR – Air Force Office of Scientific Research Program (September 2012 – August 2013)

Deterministic Aperiodic Structures for On-chip Nanophotonic and Nanoplasmonic Device Applications, funded by AFOSR – Air Force Office of Scientific Research Program (April 2012 – August 2012)

Sub-250 nm electron-beam-pumped semiconductor laser, funded by DARPA – Defense Advanced Research Projects Agency CMUVT Program under subcontract from Photon Systems Inc. (March 2011 – March 2012)

Peer-reviewed publications

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Conferences

Integration of metallic nanostructures on nanowires for modification of their optical properties
A. Casadei, E. Alarcon-Llado, E. F. Pecora, J. Trevino, C. Forestiere, D. Ruffer, E. Russo-Averchi, F. Matteini, G. Tutuncuoglu, M. Heiss, L. Dal Negro, A. Fontcuberta i Morral
Frontiers in Nanophotonics, CSF Conference 2015

Second harmonic excitation spectroscopy in studies of Fano-type coupling in plasmonic arrays
G. F. Walsh, J. Tervino, E. F. Pecora, L. Dal Negro
SPIE Optics + Photonics 2015

Engineering light coupling in single nanowire with metal nano-antennas
A. Casadei, J. Trevino, E. F. Pecora, E. Alarcò- Lladò, D. Ruffer, E. Russo-Averchi, G. Tutuncuoglu, F. Matteini, C. Forestiere, L. Dal Negro, A. Fontcuberta i Morral
International Conference on One dimensional Nanomaterials ICON 2013

Second-harmonic generation from plasmonic nanoantennas and arrays
A. Capretti, C. Forestiere, E. F. Pecora, G. Walsh, J. Trevino, S. Minissale, L. Dal Negro, G. Miano
The International Conference on Surface Plasmon Photonics SPP6

Second-harmonic generation in substoichiometric silicon nitride layers
E. F. Pecora, A. Capretti, G. Miano, L. Dal Negro
Bulletin of the American Physical Society, vol. 58, V1.00119

Rare-earth doped Si-rich ZnO for multiband near-infrared light emitting devices
E. F. Pecora, T. I. Murphy, L. Dal Negro
Bulletin of the American Physical Society, vol. 58, C23.00004

Nanopatterning of optically-active silicon nanowires
E. F. Pecora, N. Lawrence, P. Gregg, J. Trevino, P. Artoni, A. Irrera, F. Priolo, L. Dal Negro
Frontiers in Optics (FiO) – Novel Silicon Waveguides and Nanophotonics (FM4E)

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November 1, 2006July 1, 2025

PhD in Physics

Read my blog post on my research in nanowire growth and manipulation and on my research in silicon nanostructures for light emission.

Thesis

Ph.D. in Physics, summa cum laude

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Peer-reviewed publications

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Book / Book chapter

Growth, properties and processing of group IV semiconductor nanowires
E. F. Pecora
VDM Verlag Dr. Muller (August 4, 2011), ISBN: 978-3639375763

Conferences

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