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Alexandru IANCU

Assistant Researcher

Laboratory of Surface and Interface Science

alexandru[DOT]iancu[AT]infim[DOT]ro

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Alexandru-Cristi Iancu

Gender: Male

Date of birth: 15/08/1997

Nationality: Romanian

Email address: alexandru.iancu@infim.ro  Phone number: (+40) 0763629288

WORK EXPERIENCE
[ 01/08/2019 – Current ] Research Assistant (ACS)
Institutul National de Cercetare Dezvoltare pentru Fizica Materialelor (INCDFM)
City: Strada Atomistilor Nr. 405A, 077125 Magurele
Country: Romania
Main activities and responsibilities:
- Atomically cleaning thin wafers (generally germanium and silicon) by electron bombardment
- Thin film and ultra-thin film deposition by Molecular Beam Epitaxy (MBE)
- Surface characterization by X-Ray Photoelectron Spectroscopy (XPS) and Low Energy Electron Diffraction (LEED)
- General knowledge about Scanning Tunneling Microscope (STM), Auger Electron Spectroscopy (AES) and Reflection-High Energy Electron Diffraction (RHEED)

EDUCATION AND TRAINING
[ 15/09/2012 – 15/06/2016 ] Diploma de bacalaureat
Liceul Teoretic "Horia Hulubei"
Field(s) of study: Mate-Info
Level in EQF: EQF level 5
[ 01/10/2016 – 01/07/2019 ] Diploma de licenta (Bachelor's Degree)
Universitatea din Bucuresti, Facultatea de Fizica
Field(s) of study: Fizica-Informatica
Level in EQF: EQF level 6
Thesis: Investigatii computationale asupra modelului Ising
[ 01/10/2019 – 01/07/2021 ] Master's degree
Universitatea din Bucuresti, Facultatea de Fizica
Field(s) of study: Physics of Advanced Materials and Nanostructures
Level in EQF: EQF level 7
Thesis: Zirconium oxide grown on Ge(001) by molecular beam epitaxy
[ 01/10/2021 – Current ] PhD Student
Universitatea din Bucuresti, Facultatea de Fizica
Field(s) of study: Fizica starii condensate
Level in EQF: EQF level 8

Publications

1. Ferroelectric-enabled significant carbon dioxide molecular adsorption on BaTiO3(001)
Authors: Iancu, AC; Lungu, GA; Tache, CA; Teodorescu, CM

Published: NOV 11 2024, MATERIALS ADVANCES, 5, DOI: 10.1039/d4ma00856a

Carbon dioxide (CO2) is reversibly adsorbed and desorbed from ferroelectric (001) oriented, BaO-terminated barium titanate, as revealed in real time by high resolution and ultrafast photoelectron spectroscopy and certified by low energy electron diffraction. Desorption proceeds when the substrate is heated above its Curie temperature. The amount of CO2 adsorbed is derived to be between one molecule for a surface BaO unit cell (adsorption below room temperature) and one molecule for two unit cells (adsorption above room temperature). The molecule is bound with its carbon to surface oxygen, forming a CO3 structure. The BaTiO3(001) surface is unaffected by repeated cycles of adsorption-desorption. The relatively high amount of CO2 adsorbed and the stability of the substrate after repeated adsorption and desorption processes promotes barium titanate as a promising candidate for decarbonization technologies.
2. Reversible oxidation of ethylene on ferroelectric BaTiO3(001): An X-ray photoelectron spectroscopy study
Authors: Iancu, AC; Nicolaev, A; Apostol, NG; Abramiuc, LE; Teodorescu, CM

Published: AUG 15 2024, HELIYON, 10, e35072, DOI: 10.1016/j.heliyon.2024.e35072

Adsorption and desorption of ethylene on BaO-terminated (001) barium titanate are investigated by X-ray photoelectron spectroscopy. Carbon is found in an oxidized state, at a binding energy similar to that resulting from CO adsorption on BaTiO3(001). The amount of carbon adsorbed on the surface is also similar to the case of CO/BaTiO3(001). Upon heating the substrate up to the loss of its ferroelectric polarization, the C 1s signal from the oxidized spectral region vanishes. At the same time, there was no noticeable oxygen depletion of the surface after repeated C2H4 adsorption and desorption. The substrate remains stable after repeated oxidative adsorption and desorption of ethylene. Desorption occurs at different temperatures, depending on the adsorption temperature, which suggests different adsorption geometries: non-dissociated adsorption at high temperature with ethylene bond on two surface oxygen atoms, and locally dissociated adsorption at lower temperatures, in "formaldehyde-like" local configurations.
3. Molecular adsorption-desorption of carbon monoxide on ferroelectric BaTiO3(001)
Authors: Iancu, AC; Apostol, NG; Nicolaev, A; Abramiuc, LE; Chirila, CF; Popescu, DG; Teodorescu, CM

Published: JUL 15 2024, MATERIALS ADVANCES, 5, DOI: 10.1039/d4ma00389f

Carbon monoxide (CO) is reversibly adsorbed on and desorbed from ferroelectric (001) oriented, BaO-terminated barium titanate. All processes are characterized in real time via photoelectron spectroscopy. Adsorption proceeds on different sites/geometries as a function of substrate temperature. Below room temperature, CO is adsorbed on surface Ba. At room temperature, adsorption proceeds on surface oxygen, whereas at high temperatures, "hollow" site adsorption occurs with carbon coordinated with three oxygens, one oxygen initially belonging to CO and two oxygens from the substrate. The amount of CO adsorbed is about one molecule for 10 surface unit cells, which is slightly increased at low temperatures. CO is desorbed if the substrate is heated above the Curie temperature, which is a sign of the definitory role of ferroelectric polarization. The BaTiO3(001) surface is unaffected by repeated cycles of adsorption-desorption.
4. Molecular adsorption-desorption of carbon monoxide on ferroelectric BaTiO3(001)
Authors: Iancu, AC; Apostol, NG; Nicolaev, A; Abramiuc, LE; Chirila, CF; Popescu, DG; Teodorescu, CM

Published: 2024 JUN 11 2024, MATERIALS ADVANCES, DOI: 10.1039/d4ma00389f

Carbon monoxide (CO) is reversibly adsorbed on and desorbed from ferroelectric (001) oriented, BaO-terminated barium titanate. All processes are characterized in real time via photoelectron spectroscopy. Adsorption proceeds on different sites/geometries as a function of substrate temperature. Below room temperature, CO is adsorbed on surface Ba. At room temperature, adsorption proceeds on surface oxygen, whereas at high temperatures, "hollow" site adsorption occurs with carbon coordinated with three oxygens, one oxygen initially belonging to CO and two oxygens from the substrate. The amount of CO adsorbed is about one molecule for 10 surface unit cells, which is slightly increased at low temperatures. CO is desorbed if the substrate is heated above the Curie temperature, which is a sign of the definitory role of ferroelectric polarization. The BaTiO3(001) surface is unaffected by repeated cycles of adsorption-desorption.
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