Semiconductor Device Group

Silicon has long dominated microelectronics and nanoelectronics but due to the indirect bandgap and the lack of any silicon interband laser, many believe silicon is not a material for optics or photonics. There is now significant interest at integrating photonic components onto a silicon chip. This is heavily influenced by the copper interconnects for the input and output being close to the maximum bandwidth and speed. Further speed can only be achieved by moving to optical solutions and using fibre optics to transmit data.

Glasgow has been working on Si Photonics for a number of years and has developed a complete suit of devices which can be integrated together to build complete photonic circuits on top of silicon chips. Components now available include all the passives that Marc Sorel's group has been pioneering (low loss waveguides, couplers, MMIs, slow light devices, high Q cavities (Q > 150,000), delay lines, heater switches and mach-Zehnder phase shifters). My own research group has been strongly involved in looking at active devices including Ge on Si single photon avalanche detectors, quantum confined Stark effect modulators using Ge quantum wells, strain induced long wavelength emission and photodetection and frequency up and down conversion with non-linear Si photonics. We are also involved in trying to make Ge lasers and efficient LEDs for near infrared applications.

Our main focus for the research is now integrated Si photonics for quantum technology and for mid-infrared sensing applications including Ge plasmonics.

• D.J. Paul "Silicon photonics: A bright future?" Electronics Letters 45(12), pp582-584 (2009) - doi:10.1049/el.2009.1271
• D.J. Paul "Silicon photonics: A bright future?" Electronics Letters Special Supplement, pp14-16 June (2009)
• D.J. Paul, "8-band k.p modelling of the quantum confined Stark effect in Ge quantum wells on Si substrates" Physical Review B 77, 155323 (2008) - doi: 10.1103/PhysRevB.77.155323
• D.C.S. Dumas, K. Gallacher, S. Rhead, M. Myronov, D.R. Leadley and D.J. Paul, "Ge/SiGe quantum confined Stark effect electro-absorption modulation with low voltage swing at λ = 1550 nm" Optics Express 22(16), pp. 19284 - 19292 (2014) - DOI: 10.1364/OE.22.019284
• R.E. Warburton, G. Intermite, M. Myronov, P. Allred, D.R. Leadley, K. Gallacher, D.J. Paul, N.J. Pilgrim, L.J.M.Lever, Z. Ikonic, R.W. Kelsall, E. Huante-Ceron, A.P. Knights and G.S. Buller "Ge-on-Si Single-Photon Avalanche Diode Detectors: Design, Modeling, Fabrication, and Characterization at Wavelengths 1310 and 1550 nm" IEEE Transactions on Electron Devices 60, pp 3807-3813 (2013) - DOI: 10.1109/TED.2013.2282712
• D.C.S. Dumas, K. Gallacher, S. Rhead, M. Myronov, D.R. Leadley and D.J. Paul, "Ge/SiGe quantum confined Stark effect modulators with low voltage swing at  λ = 1550 nm" Proceedings of the IEEE Group IV Photonics, Paris, August (2014)
• R.W. Millar, K. Gallacher, A. Samarelli, D.C.S. Dumas, M. Myronov, D.R. Leadley and D.J. Paul, quot;Process induced tensile strain of Ge on Si nanopillars by ICP-PECVD SiN stressor layers" Proceedings of the IEEE Group IV Photonics, Paris, August (2014)
• J. Frigerio, M. Ortolani, L. Baldassarre, E. Calandrini, A. Samarelli, K. Gallacher, E. Sakat, M. Finazzi, D.J. Paul, P. Biagioni and G. Isella, "Mid-infrared Plasmonic Germanium Antennas on Silicon" Proceedings of the IEEE Group IV Photonics, Paris, August (2014)
• E. Sakat, M. Ortolani, L. Baldassarre, E. Calandrini, A. Samarelli, K. Gallacher, J. Frigerio, M. Finazzi, G. Isella, D. J. Paul, and P. Biagioni "Mid-infrared plasmonic germanium antennas integrated on a silicon substrate" Proceedings of Near-Field Optics, Nanophotonics and Related Techniques, Salt Lake City, USA (2014)
• L. Baldassarre, E. Calandrini, A. Samarelli, K. Gallacher, D.J. Paul, J. Frigerio, G. Isella, E. Sakat, M. Finazzi, P. Biagioni and M. Ortolani, "Mid-Infrared plasmonic platform based on heavily doped epitaxial Ge-on-Si: retrieving the optical constants of thin Ge epilayers" 39^th Proceedings of the International Conference on Infrared, Millimeter, and Terahertz Waves, Tucson, USA (2014) (Invited paper)
• P. Velha, K.F. Gallacher, D.C. Dumas, D.J. Paul, M. Myronov and D.R. Leadley, "Direct Band-gap Electroluminescence from Strained n-Ge Light Emitting Diodes" ECS Transactions 50, pp. 305 - 308 - DOI: 10.1149/05009.0305ecst
• P. Velha, K.F. Gallacher, D.C. Dumas, D.J. Paul, M. Myronov and D.R. Leadley, "Long Wavelength &ge 1.9 µm Germanium for Optoelectronics Using Process Induced Strain" ECS Transactions 50, pp. 779 - 782 - DOI: 10.1149/05009.0779ecst
• M. Ortolani, L. Baldassarre, A. Nucara, A. Samarelli, D.J. Paul, J. Frigerio, G. Isella, M. Finazzi and P. Biagioni, "Mid-infrared plasmonic antennas made of electron-doped epitaxial germanium-on-silicon" 39^th Proceedings of the 2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2013, pp. 1-2 - DOI: 10.1109/IRMMW-THz.2013.6665614
• G. Intermite, R.E. Warburton, M. Myronov, Phil Allred, D.R. Leadley, K. Gallagher, D.J. Paul, N.J. Pilgrim, L.J.M. Lever, Z. Ikonic, R.W. Kelsall, and G.S. Buller, "Design and performance of a prototype mesa-geometry Ge-on-Si single-photon avalanche diode detector at 1310 nm and 1550 nm wavelengths" Proceedings of 2013 IEEE 10^th International Conference onGroup IV Photonics (GFP), 2013 pp. 132 - 133 (2013) pp142 - 144 (2013) - DOI: 10.1109/Group4.2013.6644406
• P. Velha, D.C. Dumas, K. Gallacher, R. Millar, M. Myronov, D.R. Leadley and D.J. Paul, "Strained germanium nanostructures on silicon mmitting at &lambda >2.2 µm wavelength" Proceedings of 2013 IEEE 10^th International Conference onGroup IV Photonics (GFP) 2013 - DOI: 10.1109/Group4.2013.6644411
• K. Gallacher, P. Velha, D.J. Paul, S. Cecchi, J. Figerio, D. Chrastina and G. Isella, "1.55 μm direct bandgap electroluminescence from strained n-Ge quantum wells grown on Si substrates" Applied Physics Letters 101, 211101 (2012) doi 10.1063/1.4767138
• P. Velha, D. Dumas, K. Gallacher, D.J. Paul, M. Myronov and D.R. Leadley "Expanding the absorption wavelength of germanium to 2 µm using process induced strain" Optics Express (Submitted for publication)
• P. Velha, D.J. Paul, M. Myronov and D.R. Leadley, "Long Wavelength >1.9 μm Germanium for Optoelectronics Using Process Induced Strain" Electrochemical Society Transactions 50(9), pp.779-782 (2012)
• P. Velha, K. Gallacher, D. Dumas, D.J. Paul, M. Myronov and D.R. Leadley " Tuning the Electroluminescence of n-Ge LEDs using Process Induced Strain" Proceedings of the IEEE Group IV Photonics, San Diego, USA, WP3, pp.81-83 (2012) DOI: 10.1109/GROUP4.2012.6324179
• P. Velha, M. Myranov, D.R. Leadley and D.J. Paul, "Process-induced strain bandgap reduction in germanium nanostructures" CLEO: Science and Innovations (CLEO: S and I) San Jose, California, USA, May 6, 2012 Low-dimensional Photonic Structures (CTh3D) DOI: Link
• P. Velha, K. Gallacher, D.C. Dumas, M. Myronov, D.R. Leadley and D.J. Paul, "Direct band-gap electroluminescence from strained n-doped germanium diode"CLEO: Science and Innovations (CLEO: S and I) San Jose, California, USA, May 6, (2012), Novel Light-emitting Materials (CW1L) DOI: link