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
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
