Tomasz J. Ochalski
Marie Curie Researcher
Tomasz Jan Ochalski was born 3rd of September 1970 in Lublin, Poland.
High school and Master of Science degree
In 1989 Tomasz J. Ochalski finished high school with extended mathematics and physics. In the same year he started his study at the Institute of Physics at Maria Curie-Sklodowska University in Lublin. He achieved M.Sc. in physics in 1994 and title of the thesis was “Ionoluminescence of the oxidized porous silicon”. The main part of the M.Sc. work was published (list of publications nr. 2).
Doctorate
In 1994 he started Ph.D. study at his home Institute of Physics in the field of solid state physics. In 1997 he started to cooperate with the Institute of Electron Technology and for the next three years his activity was divided between these two institutes. Finally he realized two parallel projects and this resulted in two different Ph.D. thesis. He achieved doctorate in technical science and doctorate in physics almost at the same time in 2001. Ph.D. thesis accomplished in Institute of Electron Technology was entitled “High spatially resolved optical spectroscopy of the optoelectronic device structures” (September 2001) and the title of thesis correlated to Maria Curie-Sklodowska University was “Photoreflectance spectroscopy of semiconductor compounds” (December 2001). The first thesis was written on the basis of publications nr. 6, 7, 12, 14 and the second one on publications 1, 3, 4, 5.
In both cases external reviewers proposed distinction of the thesis.
Tomasz Ochalski started his own first real experiment during M.Sc. studies. He performed a number of optical experiments using high energy proton and oxygen ion beams. After short training he operated 300 keV implanter combined with mass separator. The young scientist was brave enough to maintain giant separator alone and finished his ambitious M.Sc. thesis on time.
During his first year of Ph.D. studies he was involved in building mass separator-implanter and cyclotron tandem. He was the chief of the team which projected and actuated computer-driven vacuum system of whole tandem. These facts emphasise his independent thinking and leadership ability.
After cyclotron start-up he completely devoted himself to solid state physics and particularly to optical properties of semiconductor compounds. During Ph.D. studies he built and develops photoreflectance spectrometer which was a main instrument in his experiments at Maria Curie-Sklodowska University. On his spectrometer he examined influences of epitaxial layer thickness on built-in electric field in region of GaAlAs/SI‑GaAs interface which has crucial role in field effect transistors structures.
In 1998 Tomasz Ochalski achieved TEMPUS Individual Mobility Grant (IMG). IMG allowed him to visit two laboratories at the University of Surrey, GB and Universite Montpellier II, France, both visits were two months long.
In Montpellier he built the second photoreflectance spectrometer, UV enhanced. At that time the dependence of the AlGaN band gap with alloy composition was not very well known, he investigated the bowing parameter in AlGaN alloys lattice-matched to GaN and this short visit yielded publications nr 4 and 5. These two publications were cited 30 times.
In Surrey he was rather observer and the main topic of observed experiments was modulation spectroscopy of vertical cavity surface emitting lasers (VCSEL). It was described in “Photomodulated reflectance study of InxGa1-xAs/GaAs/AlAs microcavity vertical-cavity surface emitting laser structures in the weak-coupling regime: The cavity/ground-state-exciton resonance”, P. J. Klar, G. Rowland, P. J. S. Thomas, A. Onischenko, T. E. Sale, and T. J. C. Hosea*, Phys. Rev. B 59, 2894 (1999).
After this visit he was involved in Polish Committee for Scientific Research grant for creating first polish VSCEL. During this project he started to create his own optical group specialized in photoluminescence (PL), photoluminescence excitation (PLE), electro and photoreflectance, thermoreflectance and finally in micro-Raman spectroscopy. In this project the group designed and developed prototype series of resonant cavity LEDs and VCSELs
In 1998 he achieved permanent position as en adjunct in the Institute of Electron Technology (IET) in Warsaw in Department of Physics and Technology of Low Dimensional Structures. He was a head of Laboratory of Optical Spectroscopy in this department. The Institute of Electron Technology is a major Polish research centre with the primary focus on semiconductor micro- and nanotechnology.
In 2000 he achieved grant funded by Linkoping University, Sweden. In Sweden he obtained skill and experience in time resolved spectroscopy. The big achievement in Linkoping was obtaining optically induced laser emission from polish VCSEL, this was the milestone in development electrically pumped VCSEL. Time resolved photoluminescence (TRPL) is one of the main interests of Tomasz Ochalski. Due to lack of expensive TRPL setup in Warsaw he visited Linkoping University and Max Born Institute in Berlin number of times and perform there experiments concerning dynamics of PL.
In 2002 he started 24 months long post doctoral fellowship in The Nederlands at University of Nijmegen. His main subject in Nijmegen was optical characterization of transistor structures based on nitride alloys grown on sapphire and silicon carbide. He was also involved to the project about photosensitive tips to the scanning tunnelling microscopy (STM).
In July 2006 he moved to Cork, Ireland and started his activity in Photonic Device Dynamics (PDD) group headed by Dr. Guillaume Huyet. In March 2007 Tomasz Ochalski has been awarded a Marie Curie Intra European Fellowship. He will stay with PDD group as a Marie Curie Researcher by the May 2009.
Tomasz Ochalski was involved in national and European grants:
· Semiconductor Microcavities: Technology, Physical Properties and Applications in Optoelectronic, State Committee for Scientific Research, contract 8T 11B 02018.
· Study of facet heating and degradation mechanisms in etched facet lasers, Fifth Framework Program, IST-1999- 10787-E.
· High Power High Electron Mobility Transistors based on AlGaN/GaN structure. Dutch Technical Foundation (STW).
· Spatially resolved thermoreflectance study of degradation mechanism of high power laser diode mirrors, State Committee for Scientific Research, contract 3T 11B 03128.
His main publications were cited in last years more than forty times.
Publications:
1. T.J. Ochalski, J. Żuk, L.A. Vlasukova, Effect of epitaxial layer thickness on built-in electric field in region of GaAlAs/SI‑GaAs interface: a photoreflectance study, Acta Physica Polonica 92, 935 (1997)
2. J. Zuk, T.J. Ochalski, M. Kulik, J. Liskiewicz, A.P. Kobzev, Efect of oxygen implantation on ionoluminescence of porus silicon, Journal of Luminescence 80, 935 (1997)
3. T.J. Ochalski, J. Żuk, K. Regiński, M. Bugajski, Photoreflectance studies of InGaAs/GaAs/AlGaAs single quantum well laser structures, Acta Physica Polonica A 94, 463 (1998)
4. T.J. Ochalski, B. Gil, P. Lefebvre, N. Grandjean, M. Leroux, J. Massies, S. Nakamura, H. Morkoç, Photoreflectance investigation of the bowing parameter in AlGaN alloys latice-matched to GaN, Applied Physics Letters 74, 3353 (1999)
5. T.J. Ochalski, B. Gil, P. Lefebvre, N. Grandjean, J. Massies, M. Leroux, Photoreflectance spectroscopy investigation of GaN-AlGaN quantum well structures, Physica Status Solidi (b) 216, 221 (1999)
6. T.J. Ochalski; J. Muszalski; M. Zbroszczyk; J.M. Kubica; K. Regiński; J. Katcki; M. Bugajski, Spontaneous Emission Control in InGaAs/GaAs Planar Microcavities with DBR Reflectors, Optical Properties of Semiconductor Nanostructures, ed. M. Sadowski, NATO Advanced Study, Institute Series, Plenum Press 2000 pp.201-210.
7. K. Reginski, J. Muszalski, M. Bugajski, T.J. Ochalski, J.M. Kubica, M. Zbroszczyk, J. Katcki, J. Ratajczak, MBE growth of planar microcavities with distributed brag reflectors, Thin Solid Films 367, 290 (2000)
8. J. Katcki, J. Ratajczak, K. Reginski, T.J. Ochalski, M. Bugajski, F. Phillipp, Transmission electron microscopy and photoluminescence study of laser heterostructures, Proc. Of 3rd Japanese-Polish Joint Seminar of Material Analysis, Zakopane, 2000 pp.69-72
9. H. Teisseyre, T.J. Ochalski, P. Perlin, T. Suski, M. Bugajski, W. Gebicki, The influence of erbium on the physical properties of GaN crystals grown from Nsolution in Ga at high pressure, High Presure Research 35, 18 (2000)
10. T.J. Ochalski, B Gil, P. Bigenwald, M. Bugajski, P. Lefebvre, T. Taliercio, N. Grandjean, J. Massies, The dual contribution to the Stokes-shift in InGaN-GaN quantum wells, Physica Status Solidi (b) 228, 111 (2001)
11. M. Bugajski, M. Mroziewicz, K. Reginski, J. Muszalski, J.M. Kubica, M. Zbroszczyk, P. Sajewicz, T. Piwonski, A. Jachymek, R. Rutkowski, T.J. Ochalski, A. Wojcik, E. Kowalczyk, Strained layer SCH SQW InGaAs/GaAs lasers for 980 nm band, Opto-Electr. Rev. 9, 35 (2001)
12. A. Wojcik, T.J. Ochalski, J. Muszalski, E. Kowalczyk, K. Goszczynski, M. Bugajski, Photoluminescence mapping and angle-resolved photoluminescence of MBE-grown InGaAsyGaAs RC LED and VCSEL structures, Thin Solid Films 412, 114 (2002)
13. M. Bugajski, J. Muszalski, T.J. Ochalski, J. Katcki, B. Mroziewicz, Resonant Cavity Enhanced Photonic Cevices, Acta Physica Polonica A 101, 105 (2002)
14. K. Reginski, T.J. Ochalski, J. Muszalski, M. Bugajski, J.P. Bergman, P.O. Holtz, B. Monemar, Investigations of optical properties of active regions in vertical cavity surface emmiting lasers grown by MBE, Thin Sol. Films 412, 107 (2002)
15. E. Kaminska, A. Piotrowska, K. Golaszewska, A. Barcz, R. Kruszka, T.J. Ochalski, J. Jasinski, Z. Liliental-Weber, Electrical Properties and Microstructure of Transparent ZnO Contacts to GaN, Physica Status Solidi (c) 0, 231 (2002)
16. J.Muszalski, M.Bugajski, T.J.Ochalski, B.Mroziewicz, H.Wrzesińska, M.Górska, J.Kątcki, InGaAs Resonant-Cavity Light-Emitting Diodes (RC LEDs). Proc. of SPIE, Laser Technology VII, 5230, 98 (2003)
17. A.Wójcik, T. Piwoński, T.J. Ochalski, E. Kowalczyk, M. Bugajski, A. Grzegorczyk, L. Macht, S. Haffouz, P.K. Larsen, Photoreflectance Study of GaN/AlGaN Structures. Physica Status Solidi (c) 0, 491 (2002)
18. A. Szerling, K. Kosiel, M. Płuska, T.J. Ochalski, J. Ratajczak, Oval Defects in Crystals Grown by MBE Technique: Study and Methods of Their Elimination, Electron Technology - Journal Internet 36, 1 (2004)
19. T.J. Ochalski , A. Grzegorczyk, M. Rudzinski, P.K. Larsen, E. Kowalczyk, P.O. Holtz, P. Bergman, P.P. Paskov, Optical study of AlGaN/GaN based HEMT structures, Phys. Stat. Sol. (c) 2, 2791 (2005)
20. T.J. Ochalski, T. Piwoński, D. Wawer, K. Pierściński, M. Bugajski, A. Kozłowska, A. Malag, J. Tomm, Thermoreflectance and micro-Raman measurements of the temperature distributions in broad contact laser diodes, Optica Applicata, 35, 3 (2005)
21. T.J. Ochalski , A. Grzegorczyk, M. Rudzinski, P.K. Larsen, P.O. Holtz, P. Bergman P.P. Paskov, Optical study of AlGaN/GaN based HEMT structures grown on sapphire and SiC, phys. stat. sol. (a) 202, 1300 (2005)
22. K. Pierscinski , T.J. Ochalski, M. Bugajski, An analysis of mounting strain in semiconductor structures by means of spatially resolved optical modulation techniquees, Optica Applicata 35, 0 (2005)
23. D. Wawer, T.J. Ochalski, T. Piwoński, A. Wojcik-Jedlinska, M. Bugajski, H. Page, Spatially resolved thermoreflectance study of facet temperature in quantum cascade lasers, phys. stat. sol. (a) 202, 1227 (2005)
24. D. Wawer, T.J. Ochalski, T. Piwoński, M. Szymański, M. Bugajski, Ł. Piskorski, K. Gutowski, A. Kozłowska, A. Maląg, Analysis of facet heating in semiconductor lasers, Proc. SPIE 2005. in print
25. T.J. Ochalski, D. Pierscinska1, A. Malag, Analysis of the Front Facet Temperature in Laser Diode With Non Absorbing Mirror, MRS Proc. 891, 175-178 (2006)
26. T.J. Ochalski, D. Pierscinska, K. Pierscinski, M. Bugajski, J.W. Tomm, T. Grunske, A. Kozlowska, Complementary thermoreflectance and micro-Raman analysis of facet temperatures of diode lasers, Applied Physics Letters 89, 071104 (2006)