Research Profile

Current Research - Interface and Surface Science of 2D materials, including but not limited to:

i) 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.
ii) 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 clean room high vacuum (~10-6 mbar) versus under ultra high vacuum (~10-9 mbar).
iii) Enhance the nucleation and the conformality of high-k dielectrics deposited by atomic layer deposition on TMD surfaces.
iv) Tune the covalent p-type doping of MoS2 and WSe2 via nitrogen plasma process.
v) Investigate the surface imperfections present on geological and synthetic TMDs bulk samples as well as on CVD and MBE TMD ultra-thin films.
vi) Collaborate with theory group (K, Cho, UTD) to understand several aspects related to TMD intrinsic properties such as:
    - Surface defects
    - Passivation/functionalization
    - Air stability                                  
    - Growth mechanism
    - Edge properties                            
    - Doping

We collaborate with several groups On & Off campus: C. L. Hinkle (UTD), K. Cho (UTD), C. Young (UTD), J. Robinson (PSU), D. Akinwande (UTA), H. Xing (Cornell), and Ali Javey (Berkeley).

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.

As 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 supervision of Prof. 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 quasicristal. The atomic and electronic structure of the 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 a 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.