Phone: +1.514.228.6978
Fax: +1.450.929.8102
E-mail: gitanjali.kolhatkar@emt.inrs.ca
Office: 149

Institut national de la recherche scientifique
1650, Blvd. Lionel-Boulet
Varennes (QC) J3X 1S2 CANADA

Research topics

Nanoscal functionals:
- Energy conversion
- Memory devices
- Raman study of materials for photovoltaic applications
- Biominerals

Fields of interest

- Tip-enhanced Raman spectroscopy
- AFM
- Photovoltaics

Education

PhD on Chemical beam epitaxy of III-V semiconductors and dilute nitrides for photovoltaic applications from the University of Sherbrooke.
MSc on High efficiency III-V multi-junction solar cells and tunnel junction characterisation from the University of Ottawa.

Invited talks

G.Kolhatkar, et al. (2018) "CMOS-compatible ferroelectric tunnel junctions for non-volatile memories", European Advanced Materials Congress-2018 (EAMC 2018), Stockholm, Sweden (invited talk-accepted)

G. Kolhatkar, A. Ruediger (2017). “Refractive index imaging at the nanoscale,” Entretiens Jacques Cartier 2017, Montreal, Canada (invited talk).

G. Kolhatkar, et. al, (2016). “Chemical beam epitaxty grown AlGaNAs for photovoltaic applications,” 2016 Annual conference of CMOS Emerging Technologies Research (CMOSET 2016), Montreal, Canada (invited talk).

G. Kolhatkar, et. al, (2016). “Optical near-field investigation of ferroelectric nanoparticles,” 2^nd Annual World Congress of Smart Materials-2016 (WCSM 2016), Singapore (invited talk).

Patents

A. Ruediger, H. Hadj Youssef, F. Ambriz-Vargas, G. Kolhatkar, M. A. Gauthier, R. Thomas, A. Sarkissian (2017) U.S. Patent ref.:773/14448.113 - "Ferroelectric Tunnel Junction and Method of Fabrication Thereof".

Pulications

M. Barberio, S. Valliere, M. Sciscio, G. Kolhatkar, A. Ruediger, and P. Antici, (2018) "Graphitization of Diamond by Laser-Accelerated Proton Beams", Carbon, 139, 531-537.

G. Kolhatkar, A. Merlen, J. Zhang, C. Dab, G. Q. Wallace, F. Lagugne-Labarthet, A. Ruediger, (2018) "Optical near-field mapping of plasmonic nanostructures prepared by nanosphere lithography", Beilstein Journal of Nanotechnology, 9, 1536-1543.

G. Kolhatkar, F. Ambriz-Vargas, B. Huber, R. Thomas, A. Ruediger, (2018) "Thermionic emission based resistive Memory with ultra-thin ferroelectric BiFe1-xCrxO3", Crystal Growth & Design, 18 (3), 1864-1872.

G. Kolhatkar, A. Boucherif, A. R. Boucherif, A. Dupuy, L. G. Frechette, R. Ares, A. Ruediger (2018) "Extreme temperature stability of thermally insulating graphene-mesoporous-silicon nanocomposite", Nanotechnology, 29, 145701.

G. Kolhatkar, J. Plathier, A. Ruediger (2018) "Nanoscale investigation of materials, chemical reactions, and biological systems by Tip enhanced Raman spectroscopy – A review," Journal of Materials Chemistry C, 6, 1307-1319.

C. Parisien, G. Kolhatkar, F. Crispino, A. Lajeunesse, and A. Ruediger, (2017) “Reconstruction of obliterated characters in polycarbonate through spectral imaging,” Analytical Chemistry, 89 (21), 11648-11652 * highlighted by Science Daily,  Phys. Org., and Mindsculpt.me

G. Kolhatkar, F. Ambriz-Vargas, R. Thomas, and A. Ruediger, (2017) “Microwave-assisted hydrothermal synthesis of BiFe_xCr_1-xO₃ ferroelectric thin films,” Crystal Growth & Design, 17 (11), 5967-5703.

G. Kolhatkar, J. Plathier, A. Pignolet, and A. Ruediger, (2017) “Effect of the Gold Crystallinity on the Enhanced Luminescence Signal of Scanning Probe Tips in Apertureless Near-Field Optical Microscopy,” Optics Express, 25, 25929.

F. Ambriz-Vargas, R. Nouar, G. Kolhatkar, A. Sarkissian, R. Thomas, C. Gomez-Yáñez, M. A. Gauthier, and A. Ruediger, (2017) “RF-magnetron sputtering deposition of ultra-thin Hf_0.5Zr_0.5O₂ films for non-volatile memory applications,” Materials Today: Proceedings, 4, 7000.

T. Dequivre, G. Kolhatkar, A. Hadj-Youssef, X.T. Le, G.M. Brisard, A. Ruediger, and S.A. Charlebois (2017) “Wet Metallization of High Aspect Ratio TSV Using Electrografted Polymer Insulator to Suppress Residual Stress in Silicon,” IEEE Transactions on Device and Materials Reliability.

F. Ambriz-Vargas, G. Kolhatkar, M. Broyer, A. Hadj-Youssef, R. Nouar, A. Sarkissian, R. Thomas, C. Gomez-Yáñez, M. A. Gauthier, and A. Ruediger, (2017)“A Complementary Metal Oxide Semiconductor Process-Compatible Ferroelectric Tunnel Junction,” ACS Appl. Mater. Interfaces, 9, 13262.

F. Ambriz-vargas, G. Kolhatkar, R. Thomas, R. Nouar, A. Sarkissian, C. Gomez-Yanez, M. A. Gauthier, and A. Ruediger, (2017)“Tunneling electroresistance effect in a Pt/Hf0.5Zr0.5O2/Pt structure,” Appl. Phys. Lett., vol. 110, p. 93106, 2017.

F. Ambriz-Vargas, R. Nouar, G. Kolhatkar, A. Sarkissian, R. Thomas, C. Gomez-Yáñez, M. A. Gauthier, and A. Ruediger, (2016) “RF-magnetron sputtering deposition of ultra-thin Hf_0.5Zr_0.5O₂ films for non-volatile memory applications,” Materials Today: Proceedings, 4, 7000.

A. R. Boucherif, A. Boucherif, G. Kolhatkar, A. Ruediger, and R. Arès, (2017)“Graphene-Mesoporous Si Nanocomposite as a Compliant Substrate for Heteroepitaxy,” Small, 1.* highlighted, and chosen for the cover of the May 2017 issue.

C. Dab, G. Kolhatkar, J. Plathier, R. Thomas, and A. Ruediger, (2016) “Dependence of Apertureless Scanning Near-Field Spectroscopy on Nanoscale Refractive Index Changes,” Plasmonics.

I. Velasco-Davalos, F. Ambriz-Vargas, G. Kolhatkar, R. Thomas, A. Ruediger. (2016) “Synthesis of BiFeO₃ thin films on single-terminated Nb:SrTiO₃ (111) substrates by intermittent microwave assisted hydrothermal method”, AIP Advances. 6, 065117.

G. Kolhatkar, A.Boucherif, Y. A. Bioud, S. Fafard, A. Ruediger, V. Aimez, R. Arès. (2016) “Electrical and structural properties of AlGaNAs alloys grown by chemical beam epitaxy,” Physica Status Solidi (B). 5, 1.

R. Cheriton, M. M. Wilkins, P. Sharma, C. E. Valdivia, A. H. Trojnar, H. Schriemer, J. Gupta,  B. Bouzazi, G. Kolhatkar, et al., (2015). “Design Optimizations of InGaAsN(Sb) subcells for Concentrator Photovoltaic Systems,” Journal of Vacuum Science and Technology B.34, 02M103-1.

G. Kolhatkar, A. Boucherif, C.E. Valdivia, S.G. Wallace, S. Fafard, V. Aimez, et al., (2014). “Growth optimization and optical properties of AlGaNAs alloys,” Journal of Applied Physics. 115, 163513.

G. Kolhatkar, A. Boucherif, C.E. Valdivia, S.G. Wallace, S. Fafard, V. Aimez, et al., (2013). “Al-enhanced N incorporation in GaNAs alloys grown by Chemical Beam Epitaxy,” Journal of Crystal Growth. 380, 256.

B. Paquette, M. DeVita, A. Turala, G. Kolhatkar, A. Boucherif, A. Jaouad, et al., (2013). “Optimization of p-doping in AlGaAs grown by CBE using TMA for AlGaAs/GaAs tunnel junctions,” Journal of Crystal Growth. 374, 1.

B. Paquette, M. DeVita, A. Turala, G. Kolhatkar, A. Boucherif, A. Jaouad, et al., (2013). “Chemical beam epitaxy growth of AlGaAs/GaAs tunnel junctions using trimethylaluminium for multijunction solar cells,” AIP Conference Proceeding. 1556, 48 (oral presentation and journal paper).

G. Kolhatkar, J.F. Wheeldon, C.E. Valdivia, A.W. Walker, S. Fafard, A. Turala, et al., (2012). “Current–voltage measurements within the negative differential resistance region of AlGaAs/AlGaAs tunnel junctions for high concentration photovoltaics,” International Journal of Nanoscience. 11, 1240014.

G. Kolhatkar, J.F. Wheeldon, C.E. Valdivia, S. Fafard, A. Turala, et al., (2010). “Time-dependent analysis of AlGaAs/AlGaAs Tunnel Junctions for High efficieny Multi-junction Solar Cells,” Proc. of SPIE 7750, pp. 77502S-1.

A.Walker, J.F. Wheeldon, C.E. Valdivia, G. Kolhatkar, K. Hinzer, (2010). “Simulation, modeling and comparison of III-V tunnel junction designs for high efficiency metamorphic multi-junction solar cells,” Proc. of SPIE 7750, pp. 77502X-1.

J. F. Wheeldon, C. E. Valdivia, A. Walker, G. Kolhatkar, A. Jaouad, et al., (2010). “Performance Comparison of AlGaAs, GaAs and InGaP Tunnel Junctions for Concentrated Multi-Junction Solar Cells,” Progress in Photovoltaics: Research and Applications. 19, 442.

J. F. Wheeldon, C. E. Valdivia, A. Walker, G. Kolhatkar, T. J. Hall, K. Hinzer, et al., (2010). “GaAs, AlGaAs and InGaP Tunnel Junctions for Multi-junction Solar Cells under Concentration: Resistance Study,” AIP Conference Proceeding. 1556, 48.

J. F. Wheeldon, C. E. Valdivia, A. Walker, G. Kolhatkar, T. J. Hall, et al., (2009). “AlGaAs tunnel junction for high efficiency multi-junction solar cells: simulation and measurement of temperature-dependent operation,” 34th IEEE Photovoltaic Specialist Conference 2009, Philadelphia, PA, USA, pp. 135.

Conferences

National Conference Presentations

A. Lubio, G. Kolhatkar, T. Dequivre, J. Plathier, A. Dorfler, A. Ruediger, S. A. Charlebois (2018). "The influence of thermal effects in Raman strain measurements-Analysis of Through Silicon Vias", Photonics North 2018, Montreal, Canada (oral presentation).

A. Lubio, G. Kolhatkar, T. Dequivre, A. Ruediger, S. A. Charlebois (2017). "Time-dependent stress relaxation study in through silicon vias by Raman Spectroscopy", Canadian Semiconductor Science and Technology conference (CSST) 2017, Waterloo, Canada (poster).

A. R. Boucherif, A. Boucherif, G. Kolhatkar, A. Ruediger, R. Arés (2017). "Graphene-mesoporous Si nanocomposite as a compliant substrate for heteroepitaxy", Canadian Semiconductor Science and Technology conference (CSST) 2017, Waterloo, Canada (poster).

G. Kolhatkar, F. Ambriz-Vargas, B. Huber, R. Thomas, A. Ruediger (2017). "Thermionic charge transport in hydrothermally synthesized ultrathin ferroelectric BiFe1-xCrxO3 films", GdRI-NMC 2017, Montreal, Canada (poster).

F. Ambriz-Vargas, G. Kolhatkar, R. Nouar, A. Sarkissian, R. Thomas, C. Gomez-Yanez, M. A. Gauthier, A. Ruediger (2017). "A CMOS compatible, ferroelectric tunnel junction memory", Surface Canada 2017, Montreal, Canada (poster).

F. Ambriz-Vargas, G. Kolhatkar, R. Nouar, A. Sarkissian, R. Thomas, C. Gomez-Yanez, M. A. Gauthier, A. Ruediger (2017). "A CMOS compatible, ferroelectric tunnel Junction memory", Plasma Québec 2017, Montreal Canada (poster).

A. R. Boucherif, A. Boucherif, G. Kolhatkar, A. Ruediger, R. Arès (2016). “Wafer Scale Compliant Substrate for Heteroepitaxy Based on Graphene Stabilized Porous Si Membrane,” NAMBE 2016, Saratoga Springs, NY, USA (poster).

G. Kolhatkar, F. Ambriz Vargas, A Sarkissian, R. Thomas, A. Ruediger (2016). “Bi₂FeCrO₆ thin films deposition by hydrothermal and RF-magnetron sputtering techniques,” Plasma Québec 2016, Montreal, Canada (poster).

J. Zhang, G. Kolhatkar, J. Plathier, A. Ruediger (2016). “Silver Tip Manufacturing for Tip-Enhanced Raman Spectroscopy via Electrochemical Etching,” Plasma Québec 2016, Montreal, Canada (poster).

C. Parisien, G. Kolhatkar, F. Crispino, A. Ruediger (2016). “ Reconstruction de numéro de série oblitéré sur des polymères par spectroscopie Micro-Raman et potentiel criminalistique,” Canadian Society of Forensic Science 60th anual conference, Montreal, Canada (oral presentation).

C. Parisien, G. Kolhatkar, F. Crispino, A. Ruediger (2016). “ Potentiels criminalistiques de l’imagerie spectrale pour  effectuer la révélation de numéros de série oblitérés sur des polymères,” 85^ème Association canadienne francophone pour le savoir (Acfas), Quebec City, Canada (oral presentation).

K. Hinzer, C.E. Valdivia, M. M. Wilkins, R. Cheriton, P. Sharma, A. H. Trojnar, H. Schriemer, B. Bouzazi, G. Kolhatkar et. al. (2015). “Designs optimisations for concentrated solar systems using dilute nitride four-junction photovoltaics,” Semiconductor Science and Technology Conference 2015, Sherbrooke, Canada (poster).

K. Hinzer, C.E. Valdivia, M. M. Wilkins, R. Cheriton, P. Sharma, A. H. Trojnar, H. Schriemer, B. Bouzazi, G. Kolhatkar et. al. (2015). “Designs optimisations for concentrated solar systems using dilute nitride four-junction photovoltaics,” Photonics North 2015, Ottawa, Canada (oral presentation).

C. Dab, G. Kolhatkar, J. Plathier, and A. Ruediger (2015). “Modeling of electromagnetic near field interactions with anisotropic materials in Tip-Enhanced Raman Spectroscopy,” Plasma Québec 2015, Montreal, Canada (poster).

G. Kolhatkar, A. Boucherif, S. Fafard, V. Aimez, R. Arès (2014). “Structural and Morphological Study of CBE Grown Optimisation and bandgap determination of AlGaNAs alloys for 4-junction CPV solar cells,” Next Generation Solar Photovoltaics Canada 2014, Montreal, Canada (poster).

G. Kolhatkar, A. Boucherif, C.E. Valdivia, S.G. Wallace, S. Fafard, V. Aimez, et al. (2013). “Morphology Study of GaNAs and AlGaNAs Grown by Chemical Beam Epitaxy,” NAMBE 2013, Banff, AB, Canada (oral presentation).

G. Kolhatkar, M. Wilkins, A. Turala, B. Paquette, A. Boucherif, A.Jaouad, K. Hinzer, V. Aimez et al. (2012). “GaAs/GaAs Tunnel Junctions Grown by Chemical Beam Epitaxy for Photovoltaic Applications,” Next Generation Solar 2012, Montreal, Canada (poster).

G. Kolhatkar, J.F. Wheeldon, C.E. Valdivia, R.Ares, V.Aimez, K. Hinzer, (2011). “Equivalent time-dependent nonlinear circuit for AlGaAs/AlGaAs tunnel junctions in high-efficiency multi-junction solar cells,” Photonics North 2011, Ottawa, Canada (poster).

G. Kolhatkar, J.F. Wheeldon, C.E. Valdivia, S. Fafard, A. Turala, et al., (2010). “Time-dependent analysis of AlGaAs/AlGaAs Tunnel Junctions for High efficieny Multi-junction Solar Cells,” Photonics North 2010, Niagara Falls, Canada (oral presentation).

A.Walker, J.F. Wheeldon, C.E. Valdivia, G. Kolhatkar, K. Hinzer, (2010). “Modelling and Simulation of AlGaAs, GaAs and InGaP Tunnel Junctions for Concentrator Multi-Junction Solar Cells,” Photonics North 2010, Niagara Falls, Canada (oral presentation).

International Conference Presentations

 A. Ruediger, F. Ambriz-Vargas, G. Kolhatkar, A. Hadj Youssef, A. Sarkissian, D. Drouin, S. Urquhart, R. Thomas (2018). “CMOS-compatible ferroelectric tunnel junctions based on Hf_0.5Zr_0.5O₂” IEEE-ISAF conference, Hiroshima, Japan (invited talk).

F. Ambriz-Vargas, G. Kolhatkar, R. Nouar, A. Sarkissian, R. Thomas, C. Gomez-Yanez, M. A. Gauthier, A. Ruediger (2018). "Fabrication of a CMOS compatible ferroelectric tunnel junction memory", International Conference on Metallurgical Coatings and Thin Films, San Diego, CA, USA (talk).

S. Sauze, A. Stolz, N. Semmar, G. Kolhatkar, A. Ruediger, A. Korinek, N. Braidy, S. Fafard, R. Arès, A. Boucherif, (2018). “Graphene-mesoporous Si or Ge nanocomposites for thermoelectric applications,” Porous Semiconductors-Science and Technology 2018, La Grande Motte, France (poster- accepted).

A. Boucherif, S. Sauze, A.R. Boucherif, A. Dupuy, G. Kolhatkar, A. Ruediger, S. Fafard, R. Arès (2017). “Combining graphene with 3D crystalline nanostructures: a new family of nanocomposites,” 5^th Nano Today Conference, Hawaii, USA (talk).

C. Parisien, G. Kolhatkar, A. Lajeunesse, F. Crispino, A. Ruediger (2017). “Reconstruction of obliterated serial numbers in polymers,” IAFS: 21st triennial meeting of the international association of forensic science 2017, Toronto, Canada (poster).

J. Zhang, G. Kolhatkar, J. Plathier, A. Ruediger (2017). “Silver Tip Manufacturing for Tip-Enhanced Raman Spectroscopy via Electrochemical Etching,” Advanced Materials 2017, Xi’an, China (invited talk and poster).

A. R. Boucherif, A. Boucherif, G. Kolhatkar, A. Ruediger, R. Arès (2017). “Graphene-Stabilized Porous Silicon as a Compliant Substrate for GaN heteroepitaxy,” 10th International Conference on Silicon Epitaxy and heterostructures , Coventry, UK (poster)

C. Parisien, G. Kolhatkar, F. Crispino, A. Ruediger (2016). “Reconstruction of obliterated serial numbers in polymers through Raman imaging,” The Australain and New Zealand Forensic Science Society (ANZFSS) 23^rd Symposium on the Forensic Sciences, Auckland, New Zealand (oral presentation).

G. Kolhatkar, et al, (2016). “Chemical beam epitaxty grown AlGaNAs for photovoltaic applications,” 2016 Annual conference of CMOS Emerging Technologies Research (CMOSETR 2016), Montreal, Canada (invited talk).

A. Boucherif, A. R. Boucherif, G Kolhatkar, A. Ruediger, S. Fafard, V. Aimez, R. Arès (2016). “Virtual substrates engineering with graphene coated porous Si for multijunction solar cell applications,” 2016 Annual conference of CMOS Emerging Technologies Research (CMOSETR 2016), Montreal, Canada (invited talk).

C.E. Valdivia, M. M. Wilkins, P. Sharma, R. Cheriton, A. H. Trojnar, G. Kolhatkar, et. al. (2015). “Towards CPV systems using dilute nitride-containing 4-junction solar cells,” International Conference on Concentrating Photovoltaic Systems (CPV-11), Aix-les-Bains, France (poster).

G. Kolhatkar, A. Boucherif, S. Fafard, V. Aimez, et al, (2013). “Structural and Morphological Study of CBE Grown (Al)GaNAs Alloys,” MRS Fall 2013, Boston, MA, USA (poster).

B. Paquette, M. DeVita, A. Turala, G. Kolhatkar, A. Boucherif, A. Jaouad, et al., (2013). “Chemical beam epitaxy growth of AlGaAs/GaAs tunnel junctions using trimethyl aluminium for multijunction solar cells,” International Conference on Concentrating Photovoltaic Systems (CPV-9), Miyazaki, Japan (oral presentation).

G. Kolhatkar, M. Wilkins, A. Turala, B. Paquette, A. Boucherif, A. Jaouad, et al., (2012). “Chemical Beam Epitaxy Growth of GaAs/GaAs Tunnel Junctions for Multi-junction Solar Cells,” International Conference on Concentrating Photovoltaic Systems (CPV-8), Toledo, Spain (poster).

 J. F. Wheeldon, C. E. Valdivia, A. Walker, G. Kolhatkar, T. J. Hall, K. Hinzer, et al., (2010). “GaAs, AlGaAs and InGaP Tunnel Junctions for Multi-junction Solar Cells under Concentration: Resistance Study,” International Conference on Concentrating Photovoltaic Systems (CPV-6), Freiburg, Germany (poster and journal paper).

J. F. Wheeldon, C. E. Valdivia, A. Walker, G. Kolhatkar, T. J. Hall, et al., (2009). “AlGaAs tunnel junction for high efficiency multi-junction solar cells: simulation and measurement of temperature-dependent operation,” 34th IEEE Photovoltaic Specialist Conference 2009, Philadelphia, PA, USA, pp. 135 (poster and journal paper).