M.Sc. Applied Physics, Université de Liège, Belgium, 1999.
Ph.D. Applied Physics, Universiteit Twente, The Netherlands, 2003.
Principal Member of Technical Staff thin film photovoltaics IMO-IMOMEC
Visiting professor Universiteit Hasselt
Contact: Guy.Brammertz at imec.be
Guy Brammertz graduated in 1999 from the University of Liège (Belgium) in Applied Physics. In 2003 he obtained his Ph.D. from the University of Twente (The Netherlands) defending a thesis about his work on superconducting Josephson junction photon detectors carried out for the European Space Agency. He then joined imec in 2004, where he first was involved in the LogicDram program aiming at the fabrication of Ge and III-V 35 nm gate length MOS transistors for CMOS applications. His work focused on electrical and optical characterization as well as passivation of electrical defects at Ge and III-V/oxide interfaces. In 2011 he joined the imec photovoltaic program, where he is now working on the fabrication and characterization of thin film solar cells based on Cu(In,Ga)(S,Se)2 (CIGS), Cu2ZnSn(S,Se)4 (CZTS) and Cu2ZnGe(S,Se)4 (CZGS) absorbers. Since 2017 he is visiting professor at the University of Hasselt, teaching the course of Thermodynamics in the faculty of engineering technology.
Areas of expertise
Material science.
Thin film photovoltaics.
Electrical, physical and optical characterisation of semiconductor devices.
Admittance spectroscopy.
Photoluminescence spectroscopy.
Semiconductor-oxide interfaces.
III-V MOS devices.
III-V growth by MOCVD.
Numerical analysis.
Cryogenics.
Low temperature detectors.
Selected publications (downloadable)
Thin film photovoltaics
New "Bias-Dependent Admittance Spectroscopy of Thin-Film Solar Cells: Experiment and Simulation", IEEE Journal of Photovoltaics 10 (4), 1102 (2020).
"Crystallization properties of Cu2ZnGeSe4", Thin Solid Films 670, 76 (2019).
"Fabrication of ternary and quaternary chalcogenide compounds based on Cu, Zn, Sn and Si for thin film photovoltaic applications", Physica Status Solidi C 14 (6) 1600162 (2017).
"Fabrication and characterization of ternary Cu8SiS6 and Cu8SiSe6 thin film layers for optoelectronic applications", Thin Solid Films 616, 649 (2016).
"Investigation of properties limiting efficiency in Cu2ZnSnSe4 based solar cells", IEEE Journal of Photovoltaics 5 (2), 649 (2015).
"Optoelectronic characterization of thin film Kesterite solar cells", slides presented at the Kestcells seminar at NEXCIS, Aix-en_Provence, January 2015 (2015).
"Electronic defects, secondary phases and stoichiometry control in Cu2ZnSnSe4-based solar cells", slides presented at the 5th Kesterite Workshop in Tallinn, November 2014 (2014).
"Defect characterization in Cu2ZnSnSe4-CdS-ZnO solar cells", slides presented at the PVSC in Denver, June 2014 (2014).
"Characterization of defects in 9.7 % efficient Cu2ZnSnSe4-CdS-ZnO solar cells", Applied Physics Letters 103 (16), 163904 (2013).
"Correlation between physical, electrical and optical properties of Cu2ZnSnSe4 based solar cells", Applied Physics Letters 102, 013902 (2013).
"Electrical characterization of Cu2ZnSnSe4 solar cells from selenization of sputtered metal layers", Thin Solid Films (2013).
Interface states at semiconductor-oxide interfaces
"A Combined Interface and Border Trap Model for High Mobility Substrate Metal-Oxide-Semiconductor Devices Applied to In0.53Ga0.47As and InP Capacitors", IEEE Transactions on Electron Devices (2011).
"Electrical Quality of III-V/Oxide Interfaces: Good Enough for MOSFET Devices?", ECS Transactions (2011).
"Conductance method applied to high mobility substrates", Presentation at MIT online workshop (2011).
"Electrical properties of III-V oxide interfaces", invited presentation at the IBM III-V workshop, Zurich, Switzerland (2010).
"On the interface state density at InGaAs-oxide interfaces", Applied Physics Letters (2009).
"Capacitance-Voltage Characterization of GaAs-Al2O3 interfaces", Applied Physics Letters (2008).
“Capacitance–Voltage Characterization of GaAs–Oxide interfaces”; Journal of the Electrochemical Society (2008).
“Characteristic trapping lifetime and capacitance-voltage measurements of GaAs metal-oxide-semiconductor structures”, Applied Physics Letters (2007).
"Selective epitaxial growth of GaAs on Ge by MOCVD", Journal of Crystal Growth (2006).
“Low-temperature photoluminescence study of thin epitaxial GaAs films on Ge substrates”, Journal of Applied Physics (2006).
Low temperature photon detectors
"Development of low critical temperature superconducting tunnel junctions for application as photon detectors in astronomy", PhD Thesis (2003).
"Energy-dependent kinetic model of photon absorption by superconducting tunnel junctions", Journal of Applied Physics (2003).
"Critical temperature of superconducting bilayers: theory and experiment", Applied Physics Letters (2002).
"Generalized proximity effect model in superconducting bi- and trilayer films", Journal of Applied Physics (2001).
Publications as first author
Refereed journal papers
Bias-Dependent Admittance Spectroscopy of Thin-Film Solar Cells: Experiment and SimulationG. Brammertz, T. Kohl, J. De Wild, D. G. Buldu, G. Birant, M. Meuris, J. Poortmans, B. Vermang.IEEE Journal of Photovoltaics 10 (4), 1102, 2020.