PhD open position at Institut FOTON

For years, InP was considered as a semiconductor of choice for light emitting applications (lasers, LEDs) and solar harvesting devices (photovoltaic solar cells), and was associated to excellent optical properties, but also to a high production cost. On the contrary, silicon is a well-known cost-efficient and earth abundant semiconductor. Monolithic integration of InP- based materials on Si thus offers the promise to reach high efficiency, low cost and reduced earth impact optical devices. The direct crystal growth of InP on Si is however subjected to various materials issues and generation of structural defects. In this work, the elaboration of InP/Si-based materials and nanostructures will be considered for applications in :
1- Solar hydrogen production. Indeed, the production and storage of clean, renewable, and low-cost energy is one of the challenges facing XXIst century science. The photo- electrolysis of water promises the direct conversion of solar energy into hydrogen, which can be reused to produce heat or electricity on demand. Preliminary results obtained at the Laboratory suggest that InP/Si heterostructures have a great potential to be used as photoelectrodes in photoelectrochemical cells for water splitting applications.
2- Quantum photonics. Like energy demands, fast and secure information transfer is the need of the hour. Developing emitters, detectors, and related quantum optical methodologies that operate in the lowest attenuation window (C-band) is essential for
realizing future optical quantum technologies, due to the availability of low optical losses in optical fibers and space communication channels. Ideally, one would like to obtain sources emitting at 1.55 μm spectral window, so it could be built into the currently functioning telecommunication network, as this wavelength aligns with the C-band for silicon fibers. So far, III-V-based emitters are reported only on the InP substrate, with few reports on the GaAs substrate. The III-V systems are the first choice due to their compatibility with existing networks. The realization of such sources emitting in the C-band directly on the Si substrate will open a novel area of research.

In this context, the OHM research team at “Institut FOTON” (located at INSA Rennes), which has recognized expertise at the highest international level in the mastery and understanding of solar cells and III-V on Si semiconductor materials, developed over last year’s propose Phosphide based and related materials integration on the low-cost silicon substrate with promising high yields of photo-electrodes and single photon sources/detectors. The purpose of the thesis is to develop high quality nanostructured InP/Si templates by
molecular beam epitaxy and evaluate their potential for solar hydrogen production and quantum photonics.