Main contents

Publications

Conference and journal publications

2011

  • Häyrynen, T.; Oksanen, J. and Tulkki, J.: Dynamics of cavity fields with dissipative and amplifying couplings through multiple quantum two-state systems. Physical Review A, vol. 83, no. 1, p. 013801, Jan. 2011.
  • Oksanen, J. and Tulkki, J.: Effects of photon transport, emission saturation and reflection losses on thermo-photonic cooling. Laser Refrigeration of Solids III, San Francisco, California, USA, pp. 76140F-76140F-9, 2011.
  • Heikkilä, O.; Oksanen, J. and Tulkki, J.: Transport equation model for light-emitting diodes with arbitrary surface microstructure. Physics and Simulation of Optoelectronic Devices XIX. Proceedings of the SPIE, Volume 7933, pp. 793315-793315-8, 2011.
  • Toikkanen, O.; Doan, N.; Erdmanis, M.; Lipsanen, H.; Kontturi, K. and Parviz, B.: Building Molecular Surface Gradients with Electron Beam Lithography. J. Micromech. Microeng. 21, 054025, 2011.
  • Tuomisto, F.: Vacancy defects in III-nitrides: what does positron annihilation spectroscopy reveal? Invited paper in the Proceedings of the International Workshop on Positron Studies of Defects (PSD-08), Journal of Physics: Conference Series 265, 012003, 2011.

2010

  • Rauch, C.; Reurings, F.; Tuomisto, F.; Veal, T.D.; McConville, C.F.; Lu, H.; Schaff, W.J.; Gallinat, C.S.; Koblmueller, G.; Speck, J.S. and Egger, W.: In vacancies in Si-doped InN. Proceedings of the E-MRS 2009 Fall Meeting, Symposium A, physica status solidi (a) 207, 1083–1086, 2010.
  • Reurings, F.; Tuomisto, F.; Liliental-Weber, Z.; Jones, R.E.; Yu, K.M.; Walukiewicz, W.; Schaff, W.J. and Egger, W.: Irradiation-induced defects in InN and GaN studied with positron annihilation. Physica status solidi (a), 207, 1087–1090, 2010.
  • Tuomisto, F.; Mäki, J.-M.; Ali, M.; Svensk, O.; Törmä, P.T.; Suihkonen, S. and Sopanen, M.: Defect studies with positrons: what could we learn on III-nitride heterostructures?. Invited paper in the Proceedings of the Advanced Science Research Symposium 2009, Journal of Physics: Conference Series, 225, 012057:1–6, 2010.
  • Heikkila, O.; Oksanen, J. and Tulkki, J.: The challenge of unity wall plug efficiency: The effects of internal heating on the efficiency of light emitting diodes. Journal of Applied Physics, vol. 107, Feb. 2010, pp. 033105-6.
  • Oksanen, J. and Tulkki, J.: Thermophotonic heat pump - a theoretical model and numerical simulations. Journal of Applied Physics vol. 107, no. 9, p. 093106, 2010.
  • Törmä, P.T.; Ali, M.; Svensk, O.; Suihkonen, S.; Sopanen, M.; Lipsanen, H.; Mulot, M.; Odnoblyudov, M.A. and Bougrov, V.E.: InGaN-based 405 nm near-ultraviolet light emitting diodes on pillar patterned sapphire sub-strates CrystEngComm 12, pp. 3152, 2010.
  • Sintonen, S.; Suihkonen, S.; Svensk, O.; Törmä, P.T.; Ali, M.; Sopanen, M.; Lipsanen, H. and Tuomi, T.: Characterization of InGaN/GaN and AlGaN/GaN superlattices by X-ray diffraction and X-ray reflectivity measurements. Phys. stat. sol. (c) 7, pp. 1790-1793, 2010.
  • Oksanen, J. and Tulkki, J.: Thermophotonic heat pump: towards the first demonstration of electroluminescent cooling?. Laser Refrigeration of Solids III, San Francisco, California, USA, pp. 76140F-76140F-9, 2010.
  • Reurings, F.; Rauch, C.; Tuomisto, F.; Jones, R.E.; Yu, K.M., Walukiewicz, W. and Schaff, W.J.: Defect redistribution in post-irradiation rapid-thermal-annealed InN. Physical Review B 82, 153202:1–4, 2010.
  • Koblmüller, G.; Reurings, F.; Tuomisto, F. and Speck, J.S.: Influence of Ga/N ratio on morphology, Ga vacancies and electrical transport in (0001) GaN grown by plasma-assisted molecular beam epitaxy at high temperature. Applied Physics Letters 97, 191915:1–3, 2010.
  • Reurings, F.; Tuomisto, F.; Koblmüller, G.; Gallinat, C.S. and Speck, J.S.: In vacancies in plasma-assisted molecular beam epitaxy grown InN. Applied Physics Letters 97, 251907:1–3, 2010.
  • Makkonen, I.; Snicker, A.; Puska, M.J.; Mäki, J.-M. and Tuomisto, F.: Interface sensitivity of positrons in polar semiconductor heterostructures. Physical Review B 82, 041307(R):1–4, 2010.
  • Tuomisto, F.; Mäki, J.-M. and Zajac, M.: Vacancy defects in bulk ammonothermal GaN crystals. Journal of Crystal Growth 312, 2620–2623, 2010.
  • Heikkila, O.; Oksanen, J. and Tulkki, J.: Role of the electron blocking layer in the current transport of efficient III-N light-emitting diodes. Physics and Simulation of Optoelectronic Devices XVIII, vol. 7597, pp. 75970E-8, 2010.

2009

  • Heikkilä, O.; Oksanen, J. and Tulkki, J.: Ultimate limit and temperature dependency of light-emitting diode efficiency. Journal of Applied Physics, vol. 105, p. 093119, 2009.
  • Törmä, P.T.; Ali, M.; Svensk, O.; Sintonen, S.; Kostamo, P.; Suihkonen, S.; Sopanen, M.; Lipsanen, H.; Odnoblyudov, M.A. and Bougrov, V.E.: An investigation of structural properties of GaN films grown on patterned sapphire substrates by MOVPE. Physica B. (Cond. Matter) 404, pp. 4911-4915, 2009.
  • Ali, M.; Svensk, O.; Zhen, Z.; Suihkonen, S.; Törmä, P.T.; Lipsanen, H.; Sopanen, M.; Lipsanen, H.; Hjort, K. and Jensen, J.: Reduced photoluminescence from InGaN/GaN multiple quantum well structures following 40 MeV Iodine ion irradiation. Physica B. (Cond. Matter) 404, pp. 4925-4928, 2009.
  • Törmä, P.T.; Svensk, O.; Suihkonen, S.; Ali, M.; Sopanen, M.; Odnoblyudov, M. and Bougrov, V.: Maskless roughening of the sapphire substrates for enhanced light extraction of nitride based blue LEDs, Solid State Electronics 2009, 53, pp. 166-169, 2009.
  • Oksanen, J. and Tulkki, J.: A Thermophotonic Heat Pump/Heat Engine. Proceedings of the E-MRS 2009 Fall Meeting, Materials Research Society Symposium Proceedings, 2009.
  • Heikkilä, O.; Oksanen, J. and Tulkki, J.: Numerical Optimization of Light Emitting Diodes for High Efficiency Operation. Proceedings of the E-MRS 2009 Fall Meeting, Materials Research Society Symposium, 2009.
  • Heikkilä, O.; Oksanen, J. and Tulkki, J.: The effect of temperature on the efficiency of nitride-based multi-quantum well light-emitting diodes. In Materials Research Society Symposium Proceedings, 2009.

2008

  • Suihkonen, S.; Svensk, O.; Törmä, P.T.; Muhammad, A.; Sopanen, M.; Lipsanen, H.; Odnoblyudov, M.A. and Bougrov, V.E.: MOVPE growth of InxAlyGa1-x-yN / InGaN MQW structures. Journal of Chrystal Growth 310, pp. 1777-1780, 2008.
  • Svensk, O.; Törmä, P.T.; Suihkonen, S.; Ali, M.; Lipsanen, H.; Sopanen, M.; Odnoblyudov, M. and Bougrov, V.: Enhanced Electroluminescence in 405 nm InGaN/GaN LEDs by optimized Electron Blocking Layer. Journal of Crystal Growth, 310, pp. 5154-5157, 2008.
  • Törmä, P.T.; Svensk, O.; Suihkonen, S.; Ali, M.; Lipsanen, H.; Sopanen, M.; Odnoblyudov, M. and Bougrov, V.: Effect of InGaN undeneathayer on MOVPE-grown InGaN/GaN blue LEDs. Journal of Crystal Growth 310, pp. 5162-5156, 2008.
  • Ali, M.; Suihkonen, S.; Svensk, O.; Törmä, P.T.; Sopanen, M.; Lipsanen, H.; Obnoblyudov, M.A. and Bougrov, V.E.: Study of Composition Control and Capping of MOVPE Grown In-GaN/InAlGaN MQW Structures. Phys. Stat. Sol A 5, pp. 3020-3022, 2008.

Other publications

  • Suihkonen, S.; Ali, M.; Svensk, O.; Sintonen, S.; Sopanen, M.; Lipsanen, H. and Törmä, P.T. (2010) Substrate-patterning techniques for nitride growth. SPIE Newsroom, 10 December 2010, DOI: 10.1117/2.1201010.003279.
  • Amogpai, A.; Tetri, E.; Halonen, L. (2009) New Lighting Technologies in Developing Countries-Case Sudan. 11th European Lighting Conference. Lux Europa 2009. 9-11 September, Istanbul, Turkey. 8 p.
  • Paakkinen, M.; Tetri, E.; Halonen, L. (2009) Photometric and Electrical Measurements of LED Light Engines. CIE Midterm meeting. Light and Lighting Conference with Special Emphasis on LEDs and Solid State Lighting. 27-29 May 2009. Budapest, Hungary. 8 p.

Theses

Dissertations

  • Törmä, Pekka (2011) Approaches for optimizing light emitting diode strucutres based on III-N materials. Doctoral thesis, Aalto University, 2011.
  • Reurings, Floris (2010) Slow positrons in materials science: pulsed positron beam and defect studies in indium nitride. Doctoral thesis, Aalto University, 2010.
  • Häyrynen, Teppo (2010) Quantum trajectory approach to statistics of amplified and damped cavity systems. Doctoral Thesis, Aalto University, 2010.
  • Suihkonen, Sami (2008) Fabrication of InGaN quantum wells for LED applications - InGaN-kvanttikaivojen valmistus LED-sovelluksia varten. TKK Doctoral thesis, 17.6.2008.

Master's Theses

  • Riuttanen, Lauri (2010) Thermal Annealing of AlN Thin Films Fabricated by Plasma-Enhanced Atomic Layer Deposi-tion for GaN Epitaxy. Master’s Thesis, Aalto University, 2010.
  • Kivisaari, Pyry (2010) The effect of current injection geometry on current spreading in semiconductor LEDs. Aalto University, 2010.
  • Jahkonen, Jaana (2009) Cooling of LED-luminaire. TKK Master’s Thesis, 2009.
  • Korhonen, Esa (2009) Pulssitetun positronisuihkun ohjausjärjestelmän kehitys ja tulosten analysointi. TKK Master’s thesis, 2009.
  • Quillet, Emilie (2009) Towards enhanced effciency of InGaN/GaN single quantum well Gallium Ni-tride Light Emitting Diode by plasmonic nanostructures. TKK Master’s thesis, 2009.
  • Heikkilä, Oskari (2008) Numerical modeling of high efficiency LEDs. TKK Master’s thesis, 2008.