21 Mar 2024
Job Information
- Organisation/Company
University of Rennes - CNRS- Department
IPR - Institute of Physics of Rennes (UMR 6251)- Research Field
Physics » Condensed matter properties- Researcher Profile
Recognised Researcher (R2)- Country
France- Application Deadline
24 May 2024 - 12:00 (Europe/Paris)- Type of Contract
Temporary- Job Status
Full-time- Hours Per Week
39- Is the job funded through the EU Research Framework Programme?
Not funded by an EU programme- Is the Job related to staff position within a Research Infrastructure?
No
Offer Description
Project description : The monolithic integration of III-V semiconductors on the low-cost silicon substrate has driven many fundamental and applied researches over the last past 40 years. Indeed, epitaxially combining the III-V and Si materials opens number of possibilities for e.g. sensing and lasers [1], energy production through photovoltaic solar cells [2] or energy storage through solar hydrogen production[3], [4] to name a few. Large companies, such as Intel, now believe that it could become a mainstream technology if materials properties are ultimately controlled.
At the heart of heterogeneous III-V/Si crystal growth issues is the appearance of some crystal “defects”, generated at the III-V/Si interface and propagating throughout the volume, that were historically considered as detrimental to photonic or photovoltaic applications. First, the well-known misfit dislocations originate from the lattice parameter mismatch between the III-V layer and the Si substrate. Secondly, the so-called Antiphase Boundaries (APBs) are generated by the crystal symmetry change at the III-V/Si hetero-interface. For a description of dislocations and APBs, see e.g. ref.[5]. Briefly introducing APBs, two different variants of III-V Zinc-Blende crystals can be grown on the Si Diamond structure, creating local III-III and V-V homovalent bonds inside the III-V heterovalent matrix, leading to local charge accumulation and surrounding lateral electric fields.Since the 80s, a broad literature has been dedicated to the understanding of their origin and the strategies to limit their impact on photonic and energy devices[6]. But surprisingly, only a few studiesfocused on their physical properties.
Recently, remarkable physical properties of APBs were established both experimentally and theoretically by our groups. Signature of a strong electron-phonon coupling at the APB level was for example observed in the photoluminescence spectra of III-V layers with APBS due to simultaneous efficient charge and phonon confinement in the APBs [7]. Besides, APBs band structure calculated by density functional theory also revealed exotic semi-metallic states with possible topological effects for specific APB geometries [8]. Finally, APBs were also observed to transport efficiently both electrons and holes vertically through an undoped III-V/Si photoelectrode for hydrogen production [8]. These preliminary results have led us to reconsider APBs not as redhibitory structural defects anymore but as 2D nanostructures with potentially promising intrinsic physical properties.
In this framework, the hired postdoc will join the PIANIST ANR collaborative project [9] to investigate the electronic and transport properties of APBs in III-V/Si(001) epilayers. Various III-V materials (III-P, III-Sb, III-As) with emerging APBs grown on nominal and vicinal silicon substrates by molecular beam epitaxy in the PIANIST consortium will be considered. She/He will prepare III-V self-supported membranes by Si substrate thinning and etching which will be reported on insulating or metallic substrates and contacted to probe the vertical or lateral transport properties of APBs networks. She/he will then study the APBs electrical properties in various geometries (2 probe measurements for vertical transport, 4 probe measurements with variable in-plane orientation for lateral transport, TLM, Hall effect…) and at various scales. The ultimate objective will be to address a reduced number of APBs with specific crystallographic orientation. 3D finite element simulations of the transport properties will also be considered for the interpretation of electrical characterizations. The recruited postdoc will benefit from the access to the state-of-the-art micro-nano fabrication platform NanoRennes (part of the French network Renatech+) hosted in iFOTON and to the electrical characterization lab in IPR.
[1] S. Chen et al., Nature Photonics 10, 307 (2016).
[2] M. Feifel et al., IEEE Journal of Photovoltaics 8, 1 (2018).
[3] I. Lucci et al., Advanced Functional Materials 28, 1801585 (2018).
[4] M. Alqahtani et al., Sustainable Energy & Fuels 3, 1720 (2019).
[5] C. Cornet, Y. Léger, et C. Robert, Integrated Lasers on Silicon. ISTE-Elsevier, 2016.
[6] H. Kroemer, Journal of Crystal Growth 81, 193(1987).
[7] L. Chen et al., ACS Nano 14, 13127 (2020).
[8] L. Chen et al., Advanced Science 9, 2101661 (2022).
[9] https://anr.fr/Projet-ANR-21-CE09-0020
Your qualifications: We are looking for a highly motivated, qualified and autonomous scientist interested in technological process and transport properties of semiconductor-based heterostructures. Applicants should have demonstrated expertise in semiconductor device processing in clean-room environment and their electrical characterizations. Excellent spoken and written English is mandatory.
Conditions of appointment: We offer a 1-year appointment according to the salary scheme of Rennes University. Salary depends on experience. Recruited postdoc will share her/his time between Institut FOTON (sample processing) and IPR (electrical measurements). Both laboratories are located on the Beaulieu Campus of Rennes University.
Application process: To apply, please contact Pr. Pascal Turban (IPR, [email protected] ). Your application must include a detailed CV with description of research interests, previous employments, and publication list and the contact details of at least two reference persons.
Position is open immediately. Application is open until position has been filled.
Requirements
- Research Field
- Physics » Condensed matter properties
- Education Level
- PhD or equivalent
Skills/Qualifications
We are looking for a highly motivated, qualified and autonomous scientist interested in technological process and transport properties of semiconductor-based heterostructures. Applicants should have demonstrated expertise in semiconductor device processing in clean-room environment and their electrical characterizations. Excellent spoken and written English is mandatory.
- Languages
- ENGLISH
- Level
- Excellent
Additional Information
Selection process
Position is open immediately. Application is open until position has been filled.
Work Location(s)
- Number of offers available
- 1
- Company/Institute
- University of Rennes
- Country
- France
- Geofield
Where to apply
[email protected]
Contact
- City
Rennes- Website
https://ipr.univ-rennes.fr/- Street
263 avenue Général Leclerc- Postal Code
35042
STATUS: EXPIRED