Research Profile

Dr. Rafik Addou is a highly accomplished surface scientist at Oregon State University, where he leads and manages research in the areas of ambient pressure (AP) X-ray photoelectron spectroscopy and AP scanning tunneling microscopy. With a background that spans over a decade of experience in the field, Dr. Addou holds a B.S. in Physics from Mohamed Premier University, an M.S. in Materials Physics from Aix-Marseille University, and a Ph.D. in Materials Science from Ecole des Mines de Nancy, in association with Empa Materials Science and technology laboratory.

Prior to joining Oregon State University, Dr. Addou worked as a research scientist at the University of Texas at Dallas and as a postdoctoral research fellow at the University of South Florida. His research has focused on the study of the interface and surface science of graphene and other 2D materials, including the characterization of transition metal dichalcogenides, the exploration of the interface Gr/TMDs, and in-situ studies of dielectrics and metal contacts on candidate TMDs for advanced nanoelectronic and photonic devices. He is widely recognized as an expert in thin-film technology, surface science, photoemission, and scanning tunneling microscopy.
Dr. Addou serves as a reviewer for the Royal Society of Chemistry, the American Chemical Society, the American Institute of Physics, and the Institute of Physics. With more than 80 publications to his name, including in prestigious journals such as Science, Nature Nanotechnology, Nano Letters, ACS Nano, and APL, as well as two book chapters, Dr. Addou is a highly accomplished researcher. A complete list of his publications can be found on Google Scholar.

Dr. Rafik Addou and Dr. Luigi Colombo are the editors of the book entitled "Defects in Two-Dimensional Materials," which was published by Elsevier in 2022. This publication is a testament to their expertise and leadership in the field of two-dimensional materials."

• December 2018 - February 2021
Surface Scientist and Nanoscale Analyst
College of Engineering
Oregon State University, Corvallis OR

• July 2013 - November 2018
Research Scientist
Department of Materials Science and Engineering
The University of Texas at Dallas, Richardson TX

• June 2010 - June 2013
Postdoctoral Research Physics
Physics Department

University of South Florida, Tampa FL

• November 2006 - March 2010
Research Assistant
Institut National Polytechnique de Lorraine (INPL, France) & Swiss Federal Laboratories for Materials Science and Technology (Empa, Switzerland)

• 2010 PhD, Ecole national des Mines de Nancy, Institut National Polytechnique de Lorraine (France)
• 2006 MS, Aix-Marseille University, Marseille (France)
• 2004 BS, Mohamed First University, Oujda (Morocco)

• 2015 - Electronic Materials & Processing Division Award (AVS 62nd).
• 2013 - Poster winner, best science category at the SWAN meeting(Austin, TX). 
• 2008 - First Prize for Poster presentation at the 3rd European School in Materials Sciences, Ljubljana (Slovenia)
• 2006 - Ph.D. Scholarship from European Network of Excellence for Complex Metallic Alloys.

Professional Memberships:
Materials Research Society - MRS
American Physical Society - APS
American Vacuum Society - AVS
Electrochemical Society - ECS

Research Interests
• Nanomaterials: 2D layered materials, oxides, semiconductors, topological insulators.
• Device interfaces, integration, and reliability
• Thin film technology

Researcher ID. C-8992-2013

• Recombination kinetics and effects of superacid treatment in sulfur and selenium based transition metal dichalcogenides. 
M. Amani, R. Addou, G. H. Ahn, D. Kiriya, P Taheri, D.-H. Lien, J. W. Ager, R. M. Wallace, and Ali Javey. Nano Lett., 16 (4), 2786–2791 (2016)

• The Influence of Hydroxyls on Pd-Atom Mobility and Clustering on Rutile-TiO2(011)-2×1. R. Addou, T. P. Senftle , N. O'Connor, M. J. Janik , A. C.T. van Duin, and Matthias Batzill.
ACS Nano, 8 (6), 6321–6333 (2014)

• Growth of a two-dimensional dielectric monolayer on quasi-freestanding graphene.
R. Addou, A. Dahal and M. Batzill.
Nature Nanotechnology 8, 41-45 (2013)

• Monolayer graphene growth on Ni(111) by low-temperature chemical vapor deposition.
R. Addou, A. Dahal, P. Sutter and M. Batzill.
Appl. Phys. Lett. 100 021601 (2012)

• Structure Investigation of the (100) surface of the orthorhombic Al13Co4 crystal.
R. Addou, E. Gaudry, T. Deniozou, M. Heggen, M. Feuerbacher, P. Gille, R. Widmer, O. Groening, V. Fournée, Y. Grin, J. M. Dubois, and J. Ledieu.
Phys. Rev. B 80 014203 (2009)

Most Cited Publications

1. Defect-Dominated Doping and Contact Resistance in MoS2
S. McDonnell, R. Addou, C. Buie, R. M. Wallace, C. L. Hinkle.
ACS Nano, 8, 2880–2888 (2014)
649 citations
2. Near-Unity Photoluminescence Quantum Yield in MoS2.
M. Amani, D.-H. Lien, D. Kiriya, J. Xiao, A. Azcatl, J. Noh, S. Madhvapathy, R. Addou, S. KC, M. Dubey, S.-C. Lee, Jr-H. He, J. Ager, X. Zhang, E. Yablonovitch, K. Cho, R. M. Wallace, A. Javey.
Science 350, 1065-1068 (2015)
517 citations
3. Atomically thin resonant tunnel diodes built from synthetic van der Waals heterostructures
Y.-C. Lin, R. K. Ghosh, R. Addou, N. Lu, S. M. Eichfeld, H. Zhu, M.-Y. Li, X. Peng, M. J. Kim, L.-J. Li, R. M. Wallace, S. Datta, and J. A. Robinson
Nat. Commun., 6, 7311 (2015)
316 citation
4. Manganese Doping of Monolayer MoS2: The Substrate is Critical
K. Zhang, S. Feng, J. Wang, A. Azcatl, N. Lu, R. Addou, N. Wang, C. Zhou, J. Lerach, V. Bojan, M. J. Kim, L.-Q. Chen, R. M. Wallace, M. Terrones, J. Zhu and J. A. Robinson
Nano Lett., 15, 6586–6591 (2015)
312 citations
5. Surface defects on Natural MoS2. R. Addou
L. Colombo and R. M. Wallace
ACS Appl. Mater. Interfaces, 7, 11921-11929 (2015)
275 Citations

My research focuses on the Physico-chemical characteristics of novel nanomaterials including (i) surface and interface investigation to resolve device integration challenges, (ii) surface and interface engineering for advanced electronic, photonic, and catalytic applications, and (iii) examining and depicting novel 2D materials and atomically thin films for catalysis applications. Currently, my work is featuring the use of ambient pressure X-ray photoelectron spectroscopy and scanning microscopy (AP-XPS and AP-STM) to understand the surface and interface properties in a more realistic environment.

* Research Scientist at UT Dallas (July 2013 - November 2018).

Interface and Surface Science of 2D materials.

- Growth Evaluation and Optimization of 2D materials via molecular beam epitaxy, chemical vapor transport, and chemical vapor deposition such as MoS2, WSe2, WTe2, HfSe2, MoSe2, ReS2, MoTe2, TaS2, h-BN, Te, and Bi2Se3 as well as the formation of heterostructures: WSe2/MoS2, MoS2/Graphene, and WSe2/Graphene. 
- Understand the interface chemistry between metal contacts and transition metal dichalcogenides (MoS2, WSe2, MoSe2, etc.). Provide the metal/TMD interface properties when the metal deposited in cleanroom high-vacuum (~10-6 mbar) versus under ultra-high vacuum (~10-9 mbar). 
- Enhance the nucleation and the conformality of high-k dielectrics deposited by atomic layer deposition on TMD surfaces. 
- Tune the covalent p-type doping of MoS2 and WSe2 via the nitrogen plasma process. 
Investigate the surface imperfections present on geological and synthetic TMDs bulk samples as well as on CVD and MBE TMD ultra-thin films. 
- Collaborated with the theory group at UTD (Santosh KC, Y.Nie, K. Cho) to understand several aspects related to TMD intrinsic properties such as surface defects, passivation, and functionalization, air stability, growth mechanism, edge properties, doping, etc. 

* Postdoctoral mission (June 2010 - June 2013).

I worked as postdoctoral physics associate at the Interface and Surface Science Laboratory (ISSL) with Prof. Matthias Batzill at the University of South Florida, Tampa (U.S.). Most of my research focuses on fundamental materials science issues of graphene synthesis (in particular chemical vapor deposition growth) and mechanisms and control of interface formation between graphene and dissimilar materials, i.e. formation of heterostructured materials using in-situ UHV multi-approach techniques: STM, XPS, UPS, AES, and LEED.

* PhD Student (November 2006 - March 2010).

INPL – Institut National Polytechnique de Lorraine, Nancy (France)

Thesis Title: Complex Metallic Alloy Surfaces: structure, properties and nanostructured surface.

Under the supervision of Dr. Jean-Marie DUBOIS, Dr. Julian Ledieu, and Dr. Oliver Groening

I reported the investigation of pseudo-ten-fold surfaces on two complex metallic alloys considered as approximants to the decagonal quasicrystal. The atomic and electronic structure of both samples was investigated by means of a multi-technique approach supported by ab initio electronic structure calculations. The main termination of the (100) surface of Al13Co4 is attributed to an incomplete puckered layer. The (010) surface of T-Al3(Mn, Pd) exhibits an important amount of structural imperfections. With the exception of several vacancies, this surface is identical to the complete puckered layer. In the second stage, both surfaces have been used as templates for the growth of metallic thin films. On both surfaces, Pb adatoms adopt a pseudomorphic growth mode up to one monolayer. For the Al13Co4 surface, the sticking coefficient of Pb vanishes upon the completion of the monolayer. However, it remains sufficient for the growth of additional layers on the T-Al3(Mn, Pd) (010) surface. The adsorption of Cu on the Al13Co4 surface follows also a pseudomorphic growth mode up to one monolayer. The β-Al(Cu,Co) phase appears for coverages greater than one monolayer. For higher temperature deposition, the β-phase is followed by the formation of the γ-Al4Cu9 phase. Both β and γ phases grow as two (110) domains rotated by 72 degrees from each other.

Link to the PDF dissertation

* Master Student (2004-2006).

2006 - Summer intern: Local measurement of the low energy electron transmission through auto-supported ultra-thin films. Supervisor: Dr. Alain Degiovanni.

2005 - Summer intern: Study of the phase transition and diffusion coefficient measurement on the bi-layer Phospholipids using Fluorescence Recovery After Photobleaching (FRAP) method. Supervisor: Dr. Franck Thibaudau.

Professional Experience:

• Guest Editor of a special issue of Materials (ISSN 1996-1944) entitled "2D Materials of Advanced Devices

• Editor of the new journal "Eng" which publishes papers on all areas of engineering discipline.

• November-December 2017: workshops on ‘Responsible Conduct of Research’, at UTD

• February 15, 2013: workshop on ‘Preparing and Practicing to Teach’ by the Academy for Teaching and Learning Excellence (ATLE) at USF

• October 24, 2012: workshop on ‘Mentoring: an Essential Factor for Success in Graduate School’ by Dr. Howard G. Adams at USF

• November 14-16, 2011: Visiting Brookhaven National Laboratory (BNL), New York

• October 6, 2011: Vigilent Day at USF, Topic: Science of Vacuum

• July 18-20, 2011: Visiting Brookhaven National Laboratory, New York

• February-March, 2009: Internship at the nanotech@surfaces laboratory, Empa Swiss Federal Laboratories for Materials Testing and Research, Thun (Switzerland)

• May 25-31, 2008: 3rd European School in Materials Sciences at Ljubljana (Slovenia)

• January 22-31, 2008: Visiting Berliner Elektronenspeicherring - Gesellschaft für Synchrotronstrahlung (BESSY), Berlin (Germany)

• August 2007 - March 2008: Internship at the nanotech@surfaces Empa Swiss Federal Laboratories for Materials Testing and Research

• May 20-27, 2007: 2nd European School in Materials Sciences at Ljubljana (Slovenia)

• March-June, 2005: Summer Internship at Marseille Interdisciplinary Center for Nanoscience (CINaM), France. Topic: Measurement of the low energy electron transmission through auto-supported ultra-thin films

• April-June, 2004: Summer Internship at CINaM. Topic: Study of the phase transition on the bi-layer Phospholipids using Fluorescence Recovery After Photobleaching

Useful Links:
Google Scholar
Research Gate