CNRS/C2N – Internship – Multilayer epitaxial lift-off for low-cost III-V//Si tandem solar cells

Function: Intern
Contract: Work placement agreement
Starting date: March 2023
Duration: 6 months
Workplace: IPVF – 18 Boulevard Thomas Gobert, 91120 Palaiseau (Paris-Saclay) & C2N – 10 Boulevard Thomas Gobert, 91120 Palaiseau
Education: M.S. or 3A in materials science, physical chemistry



Become an actor of the Energy Transition by joining a team driven by innovation and impact to address today’s most decisive challenges.

IPVF is one of Europe’s leading research, innovation and education organizations whose mission is to accelerate the energy transition through science and technology. Supported by the French State, IPVF is labelled Institute for Energy Transition (ITE).

Bringing together recognized industrial leaders (TotalEnergies, EDF, Air Liquide, Horiba and Riber) and world-renowned academic research teams (CNRS, Ecole Polytechnique), IPVF’ multidisciplinary and international teams conduct research dedicated to clean energy technologies (photovoltaics, green hydrogen, etc.). IPVF has built an ambitious scientific and technological research program, divided into 6 programs and 24 sub-projects, to achieve this objective.
These programs are based on a high-level experimental platform of 8,000 m², located in Paris-Saclay, and comprising more than 100 cutting-edge equipment worth €30M.





Solar cells made of III-V materials present the best efficiencies among currently available technologies, up to 47% under concentration. Nevertheless, their cost is significantly higher than mainstream silicon modules. The major part of this cost, about 80% to 90%, lies in the III-V substrates necessary for the growth of monocrystalline materials with sufficient quality. The reuse or multi-use of GaAs substrates is currently the main obstacle to lower the cost of III-V solar cells.

This project aims at developing of a novel device processing technique based on wet chemical etching and multi-epitaxy (several cells simultaneously). It will explore a new strategy to peel-off multiple layers selectively and one-by-one from a single substrate. It is based on an original “epitaxial-lift-off” approach, which will avoid the need of substrate reconditioning and reduces the growth dead-times of 10 different epitaxies to zero (pumping, degassing, annealing), resulting in a strong reduction of the cost of III-V solar cells.

The project is part of the IPVF scientific program on low-cost III-V solar cells, it is hosted by the SunLit team (C2N, CNRS) composed of both CNRS and IPVF researchers:


After a training to clean-room security and processes, the candidate will prepare an experimental setup and develop the multi-layer lift-off process. The short-term goal is to demonstrate the selective, remote-controlled, sequential etching and bonding of multiple III-V layers from a single substrate (large-surface, layer-by-layer take-and-place process). The final goal of the internship will be to use this technique to fabricate a first proof-of-concept device.


We are looking for a candidate in M2 or 3rd year of the engineering cycle, with a solid experience in materials science/physical chemistry, and strong knowledge in semiconductor physics and optics. The candidate must show good project management skills, for the development of technological procedures involving numerous parameters. Fluent communication skills in English are required for an international team (SunLit) working as well as regular presentation of work progress in internal meetings. You are expected to be able to work independently and suggest innovative solutions to reach the project objectives, and to be able to collaborate with other members of the team.



Send CV and motivation letter to:
Possibility to continue with a PhD grant on high-efficiency PV in 2023.

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