![Craig Allford](https://profiles-cardiff.imgix.net/attachments/4069?w=200&h=200&auto=format&crop=faces&fit=crop&q=90")
Dr Craig Allford
(he/him)
Research Fellow
School of Physics and Astronomy
- AllfordCP1@cardiff.ac.uk
- Translational Research Hub, Room 2.10, Maindy Road, Cathays, Cardiff, CF24 4HQ
Overview
I am a Research Fellow in Optoelectronics at the School of Physics & Astronomy, Cardiff University. I am currently employed by the EPSRC Future Compound Semicondcutor Hub whose vision is to establish the UK as the primary global research and manufacturing hub for Compound Semiconductor (CS) Technologies.
We aim to radically boost the uptake and application of CS technology by applying the manufacturing approaches of Silicon technologies to Compound Semiconductors. Enabling wide-spread exploitation of the highly advantageous electronic, magnetic, optical and power handling properties of CS materials, while utilising the cost and scaling of advantage of Silicon technology where best suited.
My focus is on the advanced characterisation of laser diodes, and long-term degradation studies of these devices. This work allows us to understand how to improve both the performance, and operating lifetimes of III-V compound semiconductor laser diodes. For this activity we have established an extensive suite of characterisation tools and equipment, which compliment the entensive range of fabrication equipment offered at Cardiff University by the Institute for Compound Semiconductors.
Publication
2023
- Albeladi, F. T. et al. 2023. Multi-mode interference reflector for integrated photonics. Presented at: 2023 IEEE Photonics Conference (IPC), 12-16 November 2023Proceedings 2023 IEEE Photonics Conference (IPC). IEEE, (10.1109/IPC57732.2023.10360650)
- Albeladi, F. T. et al. 2023. Realisation of multi-mode reflector lasers for integrated photonics. Presented at: Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 26-30 June 20232023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC). IEEE, (10.1109/CLEO/Europe-EQEC57999.2023.10231858)
- Albeladi, F. T. et al. 2023. Design and characterisation of multi-mode interference reflector lasers for integrated photonics. Journal of Physics D: Applied Physics 56(38), article number: 384001. (10.1088/1361-6463/acdb80)
- Gillgrass, S. J. et al. 2023. Impact of thermal oxidation uniformity on 150 mm GaAs- and Ge-substrate VCSELs. Journal of Physics D: Applied Physics 56(15), article number: 154002. (10.1088/1361-6463/acc040)
- Hentschel, C. et al. 2023. Gain measurements on VCSEL material using segmented contact technique. Journal of Physics D: Applied Physics 56(7), pp. 74003. (10.1088/1361-6463/acaf0b)
2022
- Baker, J. et al. 2022. VCSEL quick fabrication of 894.6 nm wavelength epi‐material for miniature atomic clock applications. IET Optoelectronics (10.1049/ote2.12082)
- Baker, J. et al. 2022. VCSEL quick fabrication for assessment of large diameter epitaxial wafers. IEEE Photonics Journal 14(3) (10.1109/JPHOT.2022.3169032)
2021
- Maglio, B. et al. 2021. The limits to peak modal gain in p-modulation doped indium arsenide quantum dot laser diodes. Presented at: 2021 IEEE Photonics Conference (IPC), Vancouver, BC, Canada, 18-21 October 20212021 IEEE Photonics Conference (IPC). IEEE pp. 1-2., (10.1109/IPC48725.2021.9592852)
- Baker, J., Gillgrass, S., Allford, C. P., Hentschel, C., Davies, J. I., Shutts, S. and Smowton, P. M. 2021. Sub-mA threshold current vertical cavity surface emitting lasers with a simple fabrication process. Presented at: 2021 IEEE Photonics Conference (IPC), 18-21 October 2021Proceedings of the 2021 IEEE Photonics Conference (IPC). IEEE, (10.1109/IPC48725.2021.9592977)
- Hentschel, C. et al. 2021. Gain measurements on vertical cavity surface emitting laser material using segmented contact technique. Presented at: 2021 IEEE Photonics Conference (IPC), 18-21 October 20212021 IEEE Photonics Conference (IPC). IEEE, (10.1109/IPC48725.2021.9592961)
- Baker, J. et al. 2021. Quick fabrication VCSELs for characterisation of epitaxial material. Applied Sciences 11(20), article number: 9369. (10.3390/app11209369)
- Mahoney, J. et al. 2021. QCSE and carrier blocking in P-modulation doped InAs/InGaAs quantum dots. Presented at: CLEO: Applications and Technology 2021, 9-14 May 2021OSA Technical Digest. , (10.1364/CLEO_AT.2021.JTU3A.167)
2020
- Li, Z. et al. 2020. Monolithic InP quantum dot mode-locked lasers emitting at 730 nm. IEEE Photonics Technology Letters 32(17), pp. 1073-1076.
- Alharbi, R., Li, Z., Allford, C. P., Shutts, S., Krysa, A. B. and Smowton, P. 2020. Design and realisation of InP mode-locked lasers emitting in the 730nm wavelength range. Presented at: Novel In-Plane Semiconductor Lasers XIX, San Francisco, CA, USA, 3-6 February 2020.
2019
- Li, Z., Shutts, S., Allford, C. P., Shi, B., Luo, W., Lau, K. M. and Smowton, P. M. 2019. Monolithic growth of InAs quantum dots lasers on (001) silicon emitting at 1.55 μm. Presented at: 2019 IEEE Photonics Conference (IPC), San Antonio, TX, USA, 2- Sept - 3 Oct 20192019 IEEE Photonics Conference (IPC). IEEE pp. 1., (10.1109/IPCon.2019.8908479)
- Li, Z., Shutts, S., Allford, C. P., Krysa, A. B. and Smowton, P. M. 2019. InP quantum dot mode-locked lasers and materials studies. Presented at: 2019 IEEE Photonics Conference (IPC), San Antonio, TX, USA, 2- Sept - 3 Oct 20192019 IEEE Photonics Conference (IPC). IEEE pp. 1., (10.1109/IPCon.2019.8908334)
- Shutts, S. et al. 2019. Degradation of III-V quantum dot lasers grown directly on silicon substrates. IEEE Journal of Selected Topics in Quantum Electronics 25(6), article number: 1900406. (10.1109/JSTQE.2019.2915994)
- Li, Z., Shutts, S., Allford, C. P., Krysa, A. B. and Smowton, P. M. 2019. 12.5-GHz InP quantum dot monolithically mode-locked lasers emitting at 740 nm. Presented at: CLEO: Science and Innovations 2019, San Jose, CA, USA, 5-10 May 2019CLEO: Science and Innovations 2019. Optical Society of America pp. SM3N.6., (10.1364/CLEO_SI.2019.SM3N.6)
- Allford, C. P. et al. 2019. InP quantum dot monolithic mode-locked lasers for ultrashort pulse generation at 735 nm. Presented at: European Semiconductor Laser Workshop 2019 (ESLW 2019), Tyndall National Institute, University College Cork, Cork, Ireland, 27-28 September 2019.
- Allford, C., Li, Z., Shutts, S., Shi, B., Luo, W., Lau, K. M. and Smowton, P. 2019. Optical gain and absorption of 1.55 um emitting InAs quantum dot lasers directly grown on (001) silicon. Presented at: European Semiconductor Laser Workshop 2019 (ESLW 2019), Tyndall National Institute, University College Cork, Cork, Ireland, 27-28 September 2019.
- Li, Z., Allford, C. P., Shutts, S., Krysa, A. B. and Smowton, P. 2019. Monolithically mode-locked self-assembled InP quantum dot lasers. Presented at: UK Semiconductors Conference 2019 (UKSC 2019), Sheffield, England. U.K., 10-11 July 2019.
- Li, Z., Shutts, S., Allford, C., Shi, B., Lua, W., Lau, K. M. and Smowton, P. 2019. Monolithic growth InAs quantum dots lasers on (001) silicon emitting at 1.5 um. Presented at: UK Semiconductors Conference 2019 (UKSC 2019), Sheffield, England. U.K., 10-11 July 2019.
- Jarvis, L. et al. 2019. Increasing gain in p-modulation-doped InAs quantum-dot lasers. Presented at: Novel In-Plane Semiconductor Lasers XIX, San Francisco, CA, USA, 3-6 February 2020.
2018
- Shutts, S., Allford, C. P., Spinnler, C., Li, Z., Tang, M., Liu, H. and Smowton, P. M. 2018. Degradation studies of InAs/GaAs QD lasers grown on Si. Presented at: ISLC 2018: 26th In ternational Semiconductor Laser Conference, Santa Fe, NM, USA, 16-19 September 20182018 IEEE International Semiconductor Laser Conference (ISLC). Piscataway, NJ: IEEE pp. 85-86., (10.1109/ISLC.2018.8516178)
- McIndo, C. et al. 2018. Optical microscopy as a probe of the rate limiting transport lifetime in InSb/Al1-xInxSb quantum wells. Journal of Physics: Conference Series 964, article number: 12005. (10.1088/1742-6596/964/1/012005)
- Allford, C. P., Gillgrass, S., Al-Ghamdi, M. S., Krysa, A. B., Shutts, S. and Smowton, P. 2018. Barrier width effects in InAsP/AlGaInP quantum dot lasers. Presented at: UK Semiconductor Conference 2018 (UKSC 2018), Sheffield, UK, 4-5 July 2018.
- McIndo, C. J., Hanks, L. A., Smith, G. V., Allford, C., Zhang, S., Clarke, E. M. and Buckle, P. 2018. Advances in electron transport in InSb/AlxIn1-xSb quantum wells. Presented at: International Symposium on Quantum Hall Effects and Related Topics (QHE2018), Max Planck Institute for Solid State Research, Stuttgart, Germany, 27-29 June 2018.
2017
- Allford, C. P. and Buckle, P. D. 2017. Strain compensated InGaAs/AlAs triple barrier resonant tunnelling structures for THz applications. IEEE Transactions on Terahertz Science & Technology 7(6), pp. 772-779. (10.1109/TTHZ.2017.2758266)
- McIndo, C. J. et al. 2017. Determination of the transport lifetime limiting scattering rate in InSb/AlxIn1−x Sb quantum wells using optical surface microscopy. Physica E: Low-dimensional Systems and Nanostructures 91, pp. 169-172. (10.1016/j.physe.2017.04.019)
- Hayes, D. G. et al. 2017. Electron transport lifetimes in InSb/Al1-x In x Sb quantum well 2DEGs. Semiconductor Science and Technology 32, article number: 85002. (10.1088/1361-6641/aa75c8)
- Smith, G. V., Hayes, D. G., Allford, C. P., Zhang, S., Clarke, E. M. and Buckle, P. 2017. Anomalous large apparent oscillation of effective g-factor in an InSb quantum well two-dimensional electron gas. Presented at: Electronic Properties of Two-Dimensional Systems 2017 (EP2DS 17), State College, PA, USA, 31 July - 4 August 2017.
2016
- Allford, C. 2016. Resonant tunnelling in GaAs/AlGaAs triple barrier heterostructures. PhD Thesis, Cardiff University.
2015
- Allford, C. P., Legg, R. E., O'Donnell, R. A., Dawson, P., Missous, M. and Buckle, P. D. 2015. Thermally activated resonant tunnelling in GaAs/AlGaAs triple barrier heterostructures. Semiconductor Science and Technology 30(10), article number: 105035. (10.1088/0268-1242/30/10/105035)
- Allford, C. P., Buckle, P. D. and Missous, M. 2015. Critical state alignment and charge accumulation in triple barrier resonant tunnelling structures. Presented at: Workshop on Compound Semiconductor Devices and Integrated Circuits 2015, Smolenice, Slovakia, 8-10 June 2015.
- Allford, C. P., Legg, R. E., O'Donnell, R. A., Dawson, P., Missous, M. and Buckle, P. D. 2015. Thermally activated resonant tunnelling in GaAs/AlGaAs triple barrier tunnelling structures. Presented at: UK Semiconductor Conference 2014 (UKSC 2014), Sheffield, UK.
Articles
- Albeladi, F. T. et al. 2023. Design and characterisation of multi-mode interference reflector lasers for integrated photonics. Journal of Physics D: Applied Physics 56(38), article number: 384001. (10.1088/1361-6463/acdb80)
- Gillgrass, S. J. et al. 2023. Impact of thermal oxidation uniformity on 150 mm GaAs- and Ge-substrate VCSELs. Journal of Physics D: Applied Physics 56(15), article number: 154002. (10.1088/1361-6463/acc040)
- Hentschel, C. et al. 2023. Gain measurements on VCSEL material using segmented contact technique. Journal of Physics D: Applied Physics 56(7), pp. 74003. (10.1088/1361-6463/acaf0b)
- Baker, J. et al. 2022. VCSEL quick fabrication of 894.6 nm wavelength epi‐material for miniature atomic clock applications. IET Optoelectronics (10.1049/ote2.12082)
- Baker, J. et al. 2022. VCSEL quick fabrication for assessment of large diameter epitaxial wafers. IEEE Photonics Journal 14(3) (10.1109/JPHOT.2022.3169032)
- Baker, J. et al. 2021. Quick fabrication VCSELs for characterisation of epitaxial material. Applied Sciences 11(20), article number: 9369. (10.3390/app11209369)
- Li, Z. et al. 2020. Monolithic InP quantum dot mode-locked lasers emitting at 730 nm. IEEE Photonics Technology Letters 32(17), pp. 1073-1076.
- Shutts, S. et al. 2019. Degradation of III-V quantum dot lasers grown directly on silicon substrates. IEEE Journal of Selected Topics in Quantum Electronics 25(6), article number: 1900406. (10.1109/JSTQE.2019.2915994)
- McIndo, C. et al. 2018. Optical microscopy as a probe of the rate limiting transport lifetime in InSb/Al1-xInxSb quantum wells. Journal of Physics: Conference Series 964, article number: 12005. (10.1088/1742-6596/964/1/012005)
- Allford, C. P. and Buckle, P. D. 2017. Strain compensated InGaAs/AlAs triple barrier resonant tunnelling structures for THz applications. IEEE Transactions on Terahertz Science & Technology 7(6), pp. 772-779. (10.1109/TTHZ.2017.2758266)
- McIndo, C. J. et al. 2017. Determination of the transport lifetime limiting scattering rate in InSb/AlxIn1−x Sb quantum wells using optical surface microscopy. Physica E: Low-dimensional Systems and Nanostructures 91, pp. 169-172. (10.1016/j.physe.2017.04.019)
- Hayes, D. G. et al. 2017. Electron transport lifetimes in InSb/Al1-x In x Sb quantum well 2DEGs. Semiconductor Science and Technology 32, article number: 85002. (10.1088/1361-6641/aa75c8)
- Allford, C. P., Legg, R. E., O'Donnell, R. A., Dawson, P., Missous, M. and Buckle, P. D. 2015. Thermally activated resonant tunnelling in GaAs/AlGaAs triple barrier heterostructures. Semiconductor Science and Technology 30(10), article number: 105035. (10.1088/0268-1242/30/10/105035)
Conferences
- Albeladi, F. T. et al. 2023. Multi-mode interference reflector for integrated photonics. Presented at: 2023 IEEE Photonics Conference (IPC), 12-16 November 2023Proceedings 2023 IEEE Photonics Conference (IPC). IEEE, (10.1109/IPC57732.2023.10360650)
- Albeladi, F. T. et al. 2023. Realisation of multi-mode reflector lasers for integrated photonics. Presented at: Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 26-30 June 20232023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC). IEEE, (10.1109/CLEO/Europe-EQEC57999.2023.10231858)
- Maglio, B. et al. 2021. The limits to peak modal gain in p-modulation doped indium arsenide quantum dot laser diodes. Presented at: 2021 IEEE Photonics Conference (IPC), Vancouver, BC, Canada, 18-21 October 20212021 IEEE Photonics Conference (IPC). IEEE pp. 1-2., (10.1109/IPC48725.2021.9592852)
- Baker, J., Gillgrass, S., Allford, C. P., Hentschel, C., Davies, J. I., Shutts, S. and Smowton, P. M. 2021. Sub-mA threshold current vertical cavity surface emitting lasers with a simple fabrication process. Presented at: 2021 IEEE Photonics Conference (IPC), 18-21 October 2021Proceedings of the 2021 IEEE Photonics Conference (IPC). IEEE, (10.1109/IPC48725.2021.9592977)
- Hentschel, C. et al. 2021. Gain measurements on vertical cavity surface emitting laser material using segmented contact technique. Presented at: 2021 IEEE Photonics Conference (IPC), 18-21 October 20212021 IEEE Photonics Conference (IPC). IEEE, (10.1109/IPC48725.2021.9592961)
- Mahoney, J. et al. 2021. QCSE and carrier blocking in P-modulation doped InAs/InGaAs quantum dots. Presented at: CLEO: Applications and Technology 2021, 9-14 May 2021OSA Technical Digest. , (10.1364/CLEO_AT.2021.JTU3A.167)
- Alharbi, R., Li, Z., Allford, C. P., Shutts, S., Krysa, A. B. and Smowton, P. 2020. Design and realisation of InP mode-locked lasers emitting in the 730nm wavelength range. Presented at: Novel In-Plane Semiconductor Lasers XIX, San Francisco, CA, USA, 3-6 February 2020.
- Li, Z., Shutts, S., Allford, C. P., Shi, B., Luo, W., Lau, K. M. and Smowton, P. M. 2019. Monolithic growth of InAs quantum dots lasers on (001) silicon emitting at 1.55 μm. Presented at: 2019 IEEE Photonics Conference (IPC), San Antonio, TX, USA, 2- Sept - 3 Oct 20192019 IEEE Photonics Conference (IPC). IEEE pp. 1., (10.1109/IPCon.2019.8908479)
- Li, Z., Shutts, S., Allford, C. P., Krysa, A. B. and Smowton, P. M. 2019. InP quantum dot mode-locked lasers and materials studies. Presented at: 2019 IEEE Photonics Conference (IPC), San Antonio, TX, USA, 2- Sept - 3 Oct 20192019 IEEE Photonics Conference (IPC). IEEE pp. 1., (10.1109/IPCon.2019.8908334)
- Li, Z., Shutts, S., Allford, C. P., Krysa, A. B. and Smowton, P. M. 2019. 12.5-GHz InP quantum dot monolithically mode-locked lasers emitting at 740 nm. Presented at: CLEO: Science and Innovations 2019, San Jose, CA, USA, 5-10 May 2019CLEO: Science and Innovations 2019. Optical Society of America pp. SM3N.6., (10.1364/CLEO_SI.2019.SM3N.6)
- Allford, C. P. et al. 2019. InP quantum dot monolithic mode-locked lasers for ultrashort pulse generation at 735 nm. Presented at: European Semiconductor Laser Workshop 2019 (ESLW 2019), Tyndall National Institute, University College Cork, Cork, Ireland, 27-28 September 2019.
- Allford, C., Li, Z., Shutts, S., Shi, B., Luo, W., Lau, K. M. and Smowton, P. 2019. Optical gain and absorption of 1.55 um emitting InAs quantum dot lasers directly grown on (001) silicon. Presented at: European Semiconductor Laser Workshop 2019 (ESLW 2019), Tyndall National Institute, University College Cork, Cork, Ireland, 27-28 September 2019.
- Li, Z., Allford, C. P., Shutts, S., Krysa, A. B. and Smowton, P. 2019. Monolithically mode-locked self-assembled InP quantum dot lasers. Presented at: UK Semiconductors Conference 2019 (UKSC 2019), Sheffield, England. U.K., 10-11 July 2019.
- Li, Z., Shutts, S., Allford, C., Shi, B., Lua, W., Lau, K. M. and Smowton, P. 2019. Monolithic growth InAs quantum dots lasers on (001) silicon emitting at 1.5 um. Presented at: UK Semiconductors Conference 2019 (UKSC 2019), Sheffield, England. U.K., 10-11 July 2019.
- Jarvis, L. et al. 2019. Increasing gain in p-modulation-doped InAs quantum-dot lasers. Presented at: Novel In-Plane Semiconductor Lasers XIX, San Francisco, CA, USA, 3-6 February 2020.
- Shutts, S., Allford, C. P., Spinnler, C., Li, Z., Tang, M., Liu, H. and Smowton, P. M. 2018. Degradation studies of InAs/GaAs QD lasers grown on Si. Presented at: ISLC 2018: 26th In ternational Semiconductor Laser Conference, Santa Fe, NM, USA, 16-19 September 20182018 IEEE International Semiconductor Laser Conference (ISLC). Piscataway, NJ: IEEE pp. 85-86., (10.1109/ISLC.2018.8516178)
- Allford, C. P., Gillgrass, S., Al-Ghamdi, M. S., Krysa, A. B., Shutts, S. and Smowton, P. 2018. Barrier width effects in InAsP/AlGaInP quantum dot lasers. Presented at: UK Semiconductor Conference 2018 (UKSC 2018), Sheffield, UK, 4-5 July 2018.
- McIndo, C. J., Hanks, L. A., Smith, G. V., Allford, C., Zhang, S., Clarke, E. M. and Buckle, P. 2018. Advances in electron transport in InSb/AlxIn1-xSb quantum wells. Presented at: International Symposium on Quantum Hall Effects and Related Topics (QHE2018), Max Planck Institute for Solid State Research, Stuttgart, Germany, 27-29 June 2018.
- Smith, G. V., Hayes, D. G., Allford, C. P., Zhang, S., Clarke, E. M. and Buckle, P. 2017. Anomalous large apparent oscillation of effective g-factor in an InSb quantum well two-dimensional electron gas. Presented at: Electronic Properties of Two-Dimensional Systems 2017 (EP2DS 17), State College, PA, USA, 31 July - 4 August 2017.
- Allford, C. P., Buckle, P. D. and Missous, M. 2015. Critical state alignment and charge accumulation in triple barrier resonant tunnelling structures. Presented at: Workshop on Compound Semiconductor Devices and Integrated Circuits 2015, Smolenice, Slovakia, 8-10 June 2015.
- Allford, C. P., Legg, R. E., O'Donnell, R. A., Dawson, P., Missous, M. and Buckle, P. D. 2015. Thermally activated resonant tunnelling in GaAs/AlGaAs triple barrier tunnelling structures. Presented at: UK Semiconductor Conference 2014 (UKSC 2014), Sheffield, UK.
Thesis
- Allford, C. 2016. Resonant tunnelling in GaAs/AlGaAs triple barrier heterostructures. PhD Thesis, Cardiff University.
Biography
Education and qualifications:
2016: PhD (Physics), Thesis: "Resonant Tunnelling in GaAs/AlGaAs Triple Barrier Heterostructure", Cardiff University, Cardiff, UK
2009: BSc Theoretical and Computational Physics, Cardiff University, Cardiff, UK.
Career Overview:
July 2022 - Present: Research Fellow, School of Physics and Astronomy, Cardiff University, Cardiff, UK
January 2018 - June 2022: Research Associate, School of Physics and Astronomy, Cardiff University, Cardiff, UK
January 2017 - December 2017: Research Fellow, School of Engineering, University of Warwick, Coventry, UK.
January 2017 - December 2017: Honorary Research Associate, School of Physics and Astronomy, Cardiff University, Cardiff, UK.
May 2016 - December 2016: Research Associate, School of Physics and Astronomy, Cardiff University, Cardiff, UK.
Professional memberships
Member of the Institute of Physics (IoP).
Supervisions
I am interested in supervising PhD students in the areas of:
- Narrow bandgap semiconductor devices (e.g. InSb Quantum Devices).
- Semicondcutor devices for the exploitation of Majorana Fermions.
- Integrated Photonic Devices.
- Advanced Laser Diode Characterisation.
Current supervision
Tom Robinson
Research student
Aisha Albeladi
Research student
Research themes
Specialisms
- Compound semiconductors
- Lasers and quantum electronics
- Light Emitting Diodes (LED)
- Quantum technologies