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Dr. Peter Mascher

Vice-Provost, International Affairs

McMaster University


Department of Engineering Physics

William Sinclair Chair in Optoelectronics

Department of Engineering Physics

Positron Annihilation Spectroscopy; Point Defects in Materials; Thin Film Technology; Silicon Nanostructures; Silicon Photonics; Luminescence; Rare Earth Doping; PECVD; Optical Characterization; Ellipsometry
Areas of Specialization:
Research Clusters:
AMH 203
+1 905.525.9140 x 24700
TAB-A110, NRB-A205
+1 905.525.9140 x 24057


Currently Accepting Graduate Students

Areas of Interest and Expertise

Defect studies in crystalline and amorphous materials Positron annihilation spectroscopy Deposition and characterization of silicon-based thin films for optoelectronic applications Aspects of plasma enhanced chemical vapour deposition Silicon photonics

In the Thin Film Laboratory, we are focusing on the Fabrication and Characterization of Nanostructures. There are several ongoing projects, among them

  • Silicon nanocrystals – a major focus of my group has been the exploration and description of the formation of silicon nanocrystals in silicon-rich oxides, nitrides, and oxy-nitrides, produced by post-deposition annealing of thin films grown by ECR-PECVD or inductively coupled plasma (ICP) CVD. Of particular interest are the effects of annealing in materials that are highly silicon rich, for applications in future nano-photonic devices. For such devices, nano-structured silicon shows substantial promise as quantum confinement effects make luminescence possible, which serves as the foundation of the rapidly emerging field of silicon photonics.
  • Rare-earth-doped structures – in collaboration with industrial partners, we have demonstrated very high, optically active concentrations of Er, Td, Ce, and Eu by using in-situ doping processes. Studies at the Canadian Light Source synchrotron facility (see below) have provided critical information on the luminescence mechanisms and the incorporation characteristics of the RE in various Si-based matrices. Most exciting form a practical perspective is the potential for tunability of the emission wavelength and/or the generation of white light.
  • Synchrotron studies – An important aspect of our work is the application of synchrotron-based techniques to the investigation of the luminescence mechanisms in rare earth doped, silicon-based structures. The results provide evidence that luminescence from these materials is correlated with the excitation of O-related energy states, and demonstrate that the composition and bonding structure of the silicon oxide host matrix play an active role in determining the luminescent properties, even though the microstructure of the films may vary from sample to sample. In order to optimize the luminescence from such materials it is, therefore, necessary to consider the local bonding environment of the RE-ions and specific details of electronic states associated with the host matrix
  • Organic Light Emitting Structures and Devices - Over the past years, we have been collaborating with W.Y. Kim’s group at Hoseo University in South Korea on the development and characterization of novel organic materials architectures for blue and white OLEDs. R. Wood, one of my former PhD students contributed substantially to a spectroscopic study of white OLEDs and B.M. Lee, one of my current PhD students, designed and fabricated blue OLEDs with double emitting layers which are doped with individual fluorescent and phosphorescent emitters. By controlling the phosphorescent doping profile, we improved the color coordinates, one of the most important parameters for practical applications.

Positrons are a unique probe of materials that provides information that is highly complementary to light, and other particle-based probes.

The McMaster Positron Laboratory is one of only three of its kind in Canada and very few in all of North America. Our work is concerned with the characterization of defect structures – principally through positron annihilation spectroscopy – in materials utilized in the development and fabrication of electronic and photonic devices. One of the most important research programs is concerned with the characterization of Cd- and Zn-based II-VI compound materials. Newer initiatives include studies of the defect chemistry of complex perovskites, which are of importance as dielectrics in microwave devices; a recently established collaboration with an industrial partner on the defect characteristics of epoxies used in semiconductor device packaging; a project on ion implantation induced amorphization of silicon as part of the processing sequence of silicon-based photonic components, and a project on intermetallic alloys.

The McMaster Intense Positron Beam Facility (MIPBF), funded jointly by the Canada Foundation of Innovation (CFI) and the Ontario Ministry of Research and Innovation (MRI), will be one of only four such facilities worldwide and will support the engineering of new materials with properties and capabilities not found in nature. By using positrons to help probe and characterize new materials, we are aiming to accelerate the development of such materials, thereby giving Ontario’s advanced manufacturing industry an important competitive advantage. The MIPBF Surface Analysis System will reduce the measurement times of surfaces from many hours to a few minutes, ensuring the integrity of the surface being probed without recourse to in-situ cleaning. This will enable the determination of the growth kinetics of ultra-thin layers on metals, semiconductors and dielectrics, as well as the detailed study of nanostructures. The Positron Defect Probe will provide the ability to probe the nature of thin layers and interfaces, with depth resolution and with spectroscopic capacity. The Positron Storage and Interaction System will allow for the accumulation of cold-trapped positrons at a rate 100 times higher than at existing facilities, enabling experiments not possible with existing positron systems, including the production of positronic atoms for precision measurements, development of formation processes applicable to antihydrogen research, and production and studies of bound molecular states consisting of matter and antimatter.


Ph.D. (1984) - Institut für Kernphysik, Technische Universität Graz, Austria

Thesis: Investigations of the Behaviour of   Positrons in Low-Melting Metals by the Lifetime Technique

 M.Eng. (1980) - Technische Universität Graz, Austria

Thesis: Positron Lifetimes in Cadmium


Peter Mascher obtained a PhD in Engineering Physics in 1984 from the Graz University of Technology (TUG) in Austria and joined McMaster University in 1989. He is a professional engineer and a professor in the Department of Engineering Physics, and chaired the department from 1994 to 2000. From 2003 to 2014 he served as the Associate Dean (Research and External Relations) of the Faculty of Engineering, with responsibilities for coordinating major research initiatives and collaborations of the Faculty. Since February 2014 he is overseeing McMaster’s International Portfolio as Vice-Provost, International Affairs. He is a Fellow of the Canadian Academy of Engineering and the Electrochemical Society. In 2015, he was appointed as an Honorary Professor at Nanjing Tech University.

Dr. Mascher holds the William Sinclair Chair in Optoelectronics and leads active research groups involved in the fabrication and characterization of thin films for optoelectronic applications, the development and application of silicon-based nanostructures, and the characterization of defects in solids by positron annihilation spectroscopy. His research work has been continuously funded for more than 27 years by the Natural Sciences and Engineering Research Council of Canada (NSERC), and has drawn funding from the Canada Foundation of Innovation (CFI), several federal and provincial Centres of Excellence, and industry, for a lifetime total surpassing $25M. Since 2010, he leads a collaborative initiative to transform the McMaster Nuclear Reactor into one of the world’s brightest positron sources for applied and fundamental research.

Dr. Mascher has supervised more than 70 graduate students and post-doctoral fellows, has authored or coauthored close to 250 publications in refereed journals and conference proceedings, and has presented many invited lectures at international conferences and workshops. He is a member of the Steering Committee of the Canadian Semiconductor Science and Technology Conference (CSSTC), the International Advisory Committee of the International Conference on Optical, Optoelectronic and Photonic Materials and Applications (ICOOPMA) and chair of the International Advisory Committee on Positron Annihilation. From 2003 to 2007 he served as the Program Director of the Ontario Photonics Consortium. Dr. Mascher served on the governing bodies of organizations as diverse as the University Network of Excellence in Nuclear Engineering (UNENE), the Steel Research Centre, the Green Auto Power Train Initiative, and the Network for the Engineering of Complex Software-Intensive Systems for Automotive Systems. He currently is a member of the Board of Directors of the Canadian Academy of Engineering and is the Vice-Chair of Nano Ontario.



Refereed Journal Publications (students and reserachers under my direct supervision are listed in italics)

Toshihiko Shibanuma, Takayuki Matsui, Jacek Wojcik, Peter Mascher, Pablo Albella, and Stefan A. Maier, “Experimental demonstration of tuneable directional scattering of visible light from all-dielectric asymmetric dimer”, ACS Photonics 4, 489 – 494 (2017); doi: 10.1021/acsphotonics.6b00979

Toudert, Johann; Serna, Rosalia; Camps, Iván; Wojcik, Jacek; Mascher, Peter; Rebollar, Esther; Ezquerra, Tiberio, “Unveiling the Far Infrared – to – Ultraviolet Optical Properties of Bismuth for Applications in Plasmonics and Nanophotonics”, The Journal of Physical Chemistry C 121, 3511 – 3521 (2017); doi: 10.1021/acs.jpcc.6b10331

Zhi-Yuan Chen, Yuqian Chen, Q. K. Zhang, N. Qi, Z.Q. Chen, P. H. Li, Peter Mascher, and S.J. Wang, “Defect evolution and their impact on the ferromagnetism of Cu-doped ZnO nanocrystals upon thermal treatment: A positron annihilation study”, Journal of Applied Physics 121, 025703 (2017); doi: 10.1063/1.4973960

Z. Khatami, P. R. J. Wilson, J. Wojcik, and P. Mascher, “The influence of carbon on the structure and photoluminescence of amorphous SiCN thin films”, Thin Solid Films 622, 1-10 (2017); doi: 10.1016/j.tsf.2016.12.014

Michal M Klak; Grzegorz Zatryb; Jacek Wojcik; Jan Misiewicz; Peter Mascher; Artur Podhorodecki, “Mechanism of enhanced photoluminescence of Tb ions in hydrogenated silicon rich silicon oxide films”, Thin Solid Films 611, 62-67 (2016); doi: 10.1016/j.tsf.2016.04.050

J. M. Ramírez, A. Ruiz-Caridad, J. Wojcik, A. M. Gutierrez, S. Estradé, F. Peiró, P. Sanchís, P. Mascher, and B. Garrido, “Bright and tunable luminescence from Ce3+ and Tb3+ codoped SiOxNy thin films: Role of nitrogen content, annealing temperature and sample morphology”, Journal of Applied Physics 119, 113108 (2016); doi: 10.1063/1.4944433

Lee, Bo Mi; Yoo, Seung Il; Kang, Jin Sung; Yoon, Ju An; Kim, Woo Young; Mascher, Peter, “Hybrid Blue Organic Light Emitting Diodes with Fluorescent and Phosphorescent Emitters along with an Interlayer”, Science of Advanced Materials 8, 301-306 (2016); doi: 10.1166/sam.2016.2483

G. Zatryb, M. Klak, J. Wojcik, J. Misiewicz, P. Mascher, and A. Podhorodecki, “Effect of hydrogen passivation on the photoluminescence of Tb ions in silicon rich silicon oxide films”, Journal of Applied Physics 118, 243104 (2015); doi: 10.1063/1.4939199

G. Zatryb, P.R.J. Wilson, J. Wojcik,  J. Misiewicz, P. Mascher, and A. Podhorodecki, “Raman scattering from confined acoustic phonons of silicon nanocrystals in silicon oxide matrix”, Physical Review B 91, 235444 (2015); doi: 10.1103/PhysRevB.91.235444

Joan Manel Ramírez, Jacek Wojcik, Yonder Berencén, Alícia Ruiz-Caridad, Sònia Estradé, Francesca Peiró, Peter Mascher, and Blas Garrido, “Amorphous sub-nanometer Tb-doped SiOxNy/SiO2 Superlattices for Optoelectronics”, Nanotechnology 26, 085203, 7 pages (2015); doi:10.1088/0975-4484/26/8/085203; PubMed ID: 25656362

G. Zatryb, J. Misiewicz, P.R.J. Wilson, J. Wojcik,  P. Mascher, and A. Podhorodecki, “Stress transition from compressive to tensile for silicon nanocrystals embedded in amorphous silica matrix”, Thin Solid Films 571, 18-22 (2014); doi: 10.1016/j.tsf.2014.09.046

A. Podhorodecki,L. W. Golacki, G. Zatryb, J. Misiewicz, J. Wang, W. Jadwisienczak, K. Fedus, J. Wojcik, P.R.J. Wilson, and P. Mascher, “Excitation mechanism and thermal emission quenching of Tb ions in silicon rich silicon oxide thin films grown by plasma-enhanced chemical vapour deposition—Do we need silicon nanoclusters?”, J. Appl. Phys. 115, 143510 (2014); doi: 10.1063/1.4871015

Bo Mi Lee, Nam Ho Kim; Ju-An Yoon; Song Eun Lee; Young Kwan Kim; Woo Young Kim; and Peter Mascher, “Luminescence Characteristics of Hybrid Dual Emitting Layers in Blue Organic Light-Emitting Diodes by Controlling the Fluorescent Doping Concentration”, J. Luminescence 148, 72-78 (2014)

Changbum Moon, Wook Song, Mei Meng, Chul-Gyu Jhun, Woo Young Kim, Richard Wood, and Peter Mascher, “Luminescence of Rubrene and DCJTB molecules in organic light-emitting devices”, J. Luminescence 146, 314-320 (2014)

Bo Mi Lee; Hyeong Hwa Yu; You Hyun Kim; Nam Ho Kim; Ju An Yoon; Woo Young Kim; Peter Mascher, “Highly Efficient Blue Organic Light-Emitting Diodes Using Dual Emissive Layers with Host-Dopant System”, J. Photon. Energy. 3, 033598 (2013); doi:10.1117/1.JPE.3.033598

A. Podhorodecki, G. Zatryb, L. Golacki, J. Misiewicz, J. Wojcik, and P. Mascher , “On the origin of emission and thermal quenching of SRSO:Er3+ films grown by ECR-PECVD”,  Nanoscale Research Letters, 8:98 (2013); doi:10.1186/1556-276X-8-98; PubMed ID 23433189

Papers in Refereed Conference Proceedings

A. Brown, S. Lyda, J. Wojcik, and P. Mascher, “Application of Titanium Nitride Coatings on Stainless Steel Tableware for Decorative and Protective Purposes”, 59th Annual Technical Conference Proceedings of the SVC (2016), pp. 319 – 324; doi: 10.14332/svc16.proc.0029

S. Bernard, P. Wilson, P. Mascher, and J. Wojcik, “A study of rare-earth doped silicon-based films as a luminescent downshifting layer for CdTe photovoltaic applications”, 57th Annual Technical Conference Proceedings of the SVC (2014), pp. 46 - 51.

J.M. Ramirez, J. Wojcik, Y. Berencén, P. Mascher, and B. Garrido, “On the photoluminescence of as-deposited Tb-doped silicon oxides and oxynitrides fabricated by ECR-PECVD”, Proc. SPIE 9133, Silicon Photonics and Photonic Integrated Circuits IV (2014), 913309 [Best Student Paper Award]

Z. Khatami, P.R.J. Wilson, J. Wojcik, and P. Mascher, “Photoluminescence Evolution of Silicon Carbonitride Thin Films Grown by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapour Deposition”, 56th Annual Technical Conference Proceedings of the SVC (2013), pp. 319 - 324

Bo Mi Lee, Nam Ho Kim, Ju-An Yoon, Woo Young Kim, and Peter Mascher, “Characterization of Hybrid Dual Emitting Layers in Blue Organic Light-Emitting Diodes by Controlling the Fluorescent Doping Concentration”, Materials Research Society (MRS) Symp. Proc. Vol. 1567 (2013) DOI: 10.1557/opl.2013.625

W. De La Cruz, S. Moodie, J. Manson, D.A. Crandles, D. Grebennikov, and P.Mascher, “Reflectance spectroscopy of Ba3+xZn1+yNb2O9 perovskites”, Prog. Electromagn. Res. Symp. 2013, pp. 225 - 228


Fellow of the Electrochemical Society (2016)

Honorary Professor, Nanjing Tech University, Nanjing, China (2015)

Fellow of the Canadian Academy of Engineering (2012)

William Sinclair Chair in Optoelectronics (since 2001)

Professional Engineer (P.Eng.) since 1993